18.09.2013 Views

Economic Production of Tannase by Aspergillus niger ... - Rombio.eu

Economic Production of Tannase by Aspergillus niger ... - Rombio.eu

Economic Production of Tannase by Aspergillus niger ... - Rombio.eu

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

Romanian Biotechnological Letters Vol.17, No.4, 2012<br />

Copyright © 2012 University <strong>of</strong> Bucharest Printed in Romania. All rights reserved<br />

ORIGINAL PAPER<br />

<strong>Economic</strong> <strong>Production</strong> <strong>of</strong> <strong>Tannase</strong> <strong>by</strong> <strong>Aspergillus</strong> <strong>niger</strong> van Tiegh Adopting<br />

Different Fermentation Protocols and Possible Applications<br />

Abstract<br />

Romanian Biotechnological Letters, Vol. 17, No. 4, 2012<br />

Received for publication, February 7, 2011<br />

Accepted, October 31, 2011<br />

H. S. HAMDY 1 AND E. M. FAWZY 2<br />

Biological Sciences & Geology Department, Faculty <strong>of</strong> Education, Ain Shams<br />

University, Roxy, Heliopolis, Cairo, 11757, Egypt<br />

1 hosamhamdy@yahoo.com 2 emanfawzy@hotmail.com<br />

Here, we demonstrated the ability <strong>of</strong> <strong>Aspergillus</strong> <strong>niger</strong> to utilize Ficus nitida' leaves and crude<br />

tannic acid extract to produce tannase. The kinetics <strong>of</strong> tannase synthesis using free and immobilised<br />

cells <strong>of</strong> A. <strong>niger</strong> were studied <strong>by</strong> adopting submerged (LSF), solid-state (SSF) and slurry-state (SlSF)<br />

cultures. The optimum parameters for maximum production were recorded at 30°C, initial pH <strong>of</strong> 5<br />

after 120 hours <strong>of</strong> shaking incubation at 175 rpm for SSF and SlSF and 200 for LSF. The maximum<br />

yield <strong>of</strong> tannase was produced in the following descending order: SSF (457.2 U 50ml -1 ) > LSF (451 U<br />

50ml -1 ) > SlSF (324.3 U 50ml -1 ). The concentration and balance <strong>of</strong> trace elements had a critical role<br />

on tannase synthesis where a dramatic beneficial effect was observed when a mixture <strong>of</strong> Ca 2+ , Mg 2+ ,<br />

Mn 2+ and Zn 2+ was added to the fermentation media. Applicability <strong>of</strong> the research findings was<br />

illustrated through suggesting the possibility <strong>of</strong> using the fermentation residue <strong>of</strong> F. nitida obtained<br />

from SSF in animal feed. Moreover, the ability <strong>of</strong> the produced tannase to remove up to 55% and 45%<br />

<strong>of</strong> tannin after 120 minute from tea extract and pomegranate juice respectively was confirmed.<br />

Keywords: <strong>Aspergillus</strong> <strong>niger</strong>, Ficus nitida, tannase, LSF, SSF, SlSF, detannification,<br />

partial purification.<br />

Introduction<br />

<strong>Tannase</strong> (tannin acylhydrolase, E.C 3.1.1.20) is an important inducible enzyme<br />

responsible for the breakdown <strong>of</strong> ester linakages in tannins and gallic acid esters to produce<br />

glucose and gallic acid [31]. <strong>Tannase</strong> has a wide range <strong>of</strong> application in industrial,<br />

biotechnological, environmental, pharmac<strong>eu</strong>tical and other important fields, such as instant<br />

tea production, clarifying c<strong>of</strong>fee-flavoured s<strong>of</strong>t drinks, removing haze, bitterness, astringency<br />

and improving the colour <strong>of</strong> fruit juices, stabilising wine color, [7, 8, 35], enzymatic treatment<br />

for nutritive use <strong>of</strong> protein and carbohydrates from peas [64], enhancing the antioxidant<br />

activity <strong>of</strong> green tea [37], and improving the quality <strong>of</strong> forage used in animal and bird feeds<br />

[50]. It is also applied in the synthesis <strong>of</strong> pharmac<strong>eu</strong>tically important drugs, i.e.,<br />

trimethoprim, gallic acid, propyl gallate, antifolic agents, antioxidants, antibacterial and<br />

antiviral agents, analgaesics, anti-inflammatories, and active anticancer agents that do not<br />

harm normal cells [11, 20, 26, 69]. <strong>Tannase</strong> is also used in the production <strong>of</strong> semiconductors,<br />

ink, dye, photo developers, [27], manufacture <strong>of</strong> sensitive analytical probes to determine<br />

gallic acid esters [24], high grade leather [6], plant cell wall degradation [49] and cleaning<br />

hard acidic industrial effluent containing tannin materials [4].<br />

In spite <strong>of</strong> the varied fields for tannase applications, the large-scale use <strong>of</strong> tannase is<br />

still limited at present, partly due to the shortage and high cost <strong>of</strong> the enzyme production [65].<br />

This could partly be due to the high price <strong>of</strong> the enzymes produced <strong>by</strong> submerged<br />

fermentation and the relatively high cost <strong>of</strong> tannic acid used as the substrate. On the other<br />

hand, there is <strong>of</strong>ten a serious problem in disposing agricultural residues and wastes, which<br />

7441


H. S. HAMDY AND E. M. FAWZY<br />

may cause serious environmental contamination and propagation <strong>of</strong> flies and rats if not<br />

correctly dealt with. Meanwhile, agricultural wastes can represent large renewable resources<br />

for enzyme production <strong>by</strong> filamentous fungi and has been practiced worldwide as waste-based<br />

cultures adopting solid state fermentation [67]. To bridge this gap, alternative techniques<br />

such as solid/slurry state fermentations, use <strong>of</strong> whole-cell-immobilization, and/or use <strong>of</strong> less<br />

expensive substrates such as agricultural residues may be used in obtaining relevant costeffective<br />

products such as enzymes and forage among others. In Egypt, Ficus nitida L.<br />

(Moraceae) is a widely cultivated ornamental plant that annually yields a vast amount <strong>of</strong> waste<br />

in the form <strong>of</strong> leaves. Although Ficus wastes are highly nutritious for microorganisms [29],<br />

there is still no study that examines its potential use as a bioresource for tannase production.<br />

Solid state fermentation (SSF) is a batch process used for its many advantages such as<br />

the low cost <strong>of</strong> raw materials, simple equipments and facilities, labour and technology.<br />

Moreover, the secreted enzymes in the culture filtrate are more concentrated and <strong>of</strong> higher<br />

quality, with a less effluent generated and lower a lower cost <strong>of</strong> recovery than in the liquid<br />

state cultures [43]. It is also a natural environment that provides easy aeration, high surface<br />

exchange and serves as a support for the cells [44]. Along with the SSF, there is a growing<br />

interest in the whole-immobilized cells to produce enzymes as a promising technique<br />

proposed for improving the fermentation process where it <strong>of</strong>fers several advantages, i.e., easy<br />

to handle, r<strong>eu</strong>sable, continuous operation over a prolonged period with operational stability,<br />

reducing the overall cost and delays associated with the time needed for sterilisation,<br />

inoculation and mycelium growth, lower susceptibility to microbial contamination, lower<br />

vulnerability to inhibitory compounds and nutrient depletion, and increased rates <strong>of</strong><br />

generating <strong>of</strong> microbial products [17, 51]. Meanwhile, very little information can be found in<br />

the literature about slurry state fermentation and their applications are mostly restricted to<br />

anaerobic fermentations [18].<br />

Many fungal species have been reported to produce tannase, including <strong>Aspergillus</strong><br />

aculeatus, A. aur<strong>eu</strong>s, A. flavus, A. foetidus, A. japonicas, A. <strong>niger</strong>, A. oryzae Aureobasidium<br />

pullulans, Fusarium solani F. subglutinans, Paecilomyces variotii, Penicillium<br />

atramentosum; P.chrysogenum, P. variable, and R. oryzae as reviewed <strong>by</strong> Belur and<br />

Mugeraya [10] and Chavez-Gonzalez [16]. The vast majority produce in submerged cultures,<br />

while <strong>Aspergillus</strong> and Penicillium are the most active microorganisms capable <strong>of</strong> producing<br />

tannase through both submerged and solid state fermentations [45, 46]. Different agricultural<br />

residues such as cassava, carob bean, wine-grape, tea and c<strong>of</strong>fee wastes, [65]; Acacia nilotica,<br />

A. auriculiformis, Casuarina equisetifolia, Cassia fistula, Ficus benghalensis, [39] and<br />

gobernadora [62], have been associated with microbial production <strong>of</strong> tannase on SSF, while<br />

many studies have investigated tannase production with pure tannic acid as the soul carbon<br />

source [39].<br />

Thus, the aim <strong>of</strong> this study was to investigate, compare and optimise production <strong>of</strong><br />

tannase utilising crude tannic acid extract and leaves <strong>of</strong> F. nitida adopting LSF, SSF and SlSF<br />

protocols inoculated with free and immobilised cells <strong>of</strong> A. <strong>niger</strong>. Possible applications <strong>of</strong> the<br />

produced tannase as well as the fermentation residue are also suggested.<br />

Materials and Methods<br />

Preparation <strong>of</strong> materials and equipments<br />

Plant leaves were collected in May from mature trees <strong>of</strong> Ficus nitida, cultivated in<br />

different Egyptian localities, cut into small pieces, and then oven-dried at 55°C for 24 h until<br />

they reached a constant weight. The material was then finely ground to pass through a 50μm<br />

sieve. The powder was stored in dry flasks under dark conditions at room temperature.<br />

7442 Romanian Biotechnological Letters, Vol. 17, No. 4, 2012


<strong>Economic</strong> <strong>Production</strong> <strong>of</strong> <strong>Tannase</strong> <strong>by</strong> <strong>Aspergillus</strong> <strong>niger</strong> van Tiegh<br />

Adopting Different Fermentation Protocols and Possible Applications<br />

Crude tannin extract was prepared according to the method <strong>of</strong> Schanderi [55] where<br />

50 g <strong>of</strong> dry plant materials were mixed with 200 ml <strong>of</strong> distilled water and kept at room<br />

temperature overnight. After soaking, the mixture was boiled for 10 min and filtered. The<br />

filtrate served as a crude tannin extract from which different dilutions were prepared using<br />

distilled water.<br />

Cleaning <strong>of</strong> equipments used in studying the requirements <strong>of</strong> metallic nutrition was<br />

performed <strong>by</strong> washing in hot detergent solution, rinsing in tap water, drying and submerging<br />

in a bath <strong>of</strong> hot, concentrated nitric-sulphuric acid (2:1) for 15 minutes. The glassware was<br />

removed from this bath and rinsed 5 times with distilled water and finally 2 times with glassdistilled<br />

water.<br />

Microorganism<br />

<strong>Aspergillus</strong> <strong>niger</strong> van Tiegh CBC 122722 used throughout this work was previously<br />

isolated from an Egyptian soil sample, identified <strong>by</strong> the CBS-KNAW (Fungal Biodiversity<br />

Centre, Uppsalalaan, Netherlands) and kept on malt extract agar at 4 °C and routinely<br />

cultured.<br />

Spore suspension (containing about 2 x 10 6 spores ml -1 ) was freshly prepared from 7day-old<br />

cultures <strong>of</strong> A. <strong>niger</strong> grown on malt extract agar slants at 30°C using deionised double<br />

distilled water.<br />

Entrapped spores <strong>of</strong> A. <strong>niger</strong> was prepared according to the method described <strong>by</strong><br />

Yalcinkaya [71] where 10 ml <strong>of</strong> 5% Na-alginate was mixed with 1 ml <strong>of</strong> the fungal spore<br />

suspension. The mixture was introduced into a solution containing 0.1 M CaCl2 with a<br />

syringe with a constant stirring to prevent aggregation <strong>of</strong> the beads. The fungal sporeentrapped<br />

beads (about 2.5 mm in diameter to overcome the anaerobic conditions inside the<br />

large beads [60]) were cured in this solution for 1 h and then washed twice with 200 ml <strong>of</strong><br />

sterile distilled water. The beads with immobilised spores (about 20 ml volume) were then<br />

transferred to the fermentation medium.<br />

Screening<br />

The potential <strong>of</strong> different fungal strains for tannase production was screened in tannic<br />

acid medium composed <strong>of</strong> (g/l): freshly prepared filter-sterilised tannic acid (30g), (NH4)2SO4<br />

(2g), KH2PO4 (0.5g), MgSO4 (2g), and agar agar (30g) [4]. The tannase-producing organisms<br />

were grown according to one <strong>of</strong> the following fermentation protocols.<br />

Enzyme production and fermentation media<br />

(A) Batch cultures<br />

Flasks containing one <strong>of</strong> the following fermentation media were prepared in<br />

triplicates, the initial pH value adjusted to 5.5, and incubated for 96 h at 30°C under static and<br />

shaking conditions (GFL shaking incubator, 150 rpm).<br />

Liquid state fermentation (LSF) medium<br />

Liquid state fermentation (LSF) medium was composed <strong>of</strong> (g/l): freshly prepared<br />

filter-sterilised crude tannin extract (30g), (NH4)2SO4 (2.0g), K2HPO4 (0.5g) and<br />

MgSO4.7H2O (1.0g) in a final volume <strong>of</strong> 50 ml per flask [4]. Medium was inoculated with 1<br />

ml <strong>of</strong> free A. <strong>niger</strong> spore suspension, or with about 20 ml <strong>of</strong> immobilised cells.<br />

Solid state fermentation (SSF)<br />

Five ml <strong>of</strong> LSF medium without any <strong>of</strong> the carbon (crude tannin extract) and nitrogen<br />

((NH4)2SO4) sources were added to 10 g <strong>of</strong> powdered Ficus nitida leaves and inoculated with<br />

1 ml <strong>of</strong> free spore suspension.<br />

Romanian Biotechnological Letters, Vol. 17, No. 4, 2012 7443


H. S. HAMDY AND E. M. FAWZY<br />

Slurry state fermentation (SlSF)<br />

Similar sets <strong>of</strong> flasks used in SSF were prepared, while an extra amount <strong>of</strong> 45 ml <strong>of</strong><br />

distilled water was added to the medium to set the slurry state condition (SlSF) and then were<br />

inoculated with 1 ml <strong>of</strong> free spore suspension.<br />

(B) Repeated batch cultures<br />

Flasks (LSF) inoculated with immobilised spores were incubated for 120 hours at the<br />

first cycle to allow the mycelium to develop and then the duration <strong>of</strong> each cycle was 48 hour.<br />

At the end <strong>of</strong> each run the beads were aseptically filtered, washed thoroughly with 25 ml<br />

saline, acetate buffer (0.2 M, pH 5) and distilled water and then recultivated into 50 ml<br />

aliquots <strong>of</strong> fresh medium.<br />

Enzyme extraction<br />

At the end <strong>of</strong> incubation, the cell-free filtrate in LSF was obtained <strong>by</strong> filtering through<br />

Whatman No. 1 filter paper in a Buchner funnel. In SSF and SlSF, a suitable amount <strong>of</strong> the<br />

fermented matter was thoroughly mixed with 10 ml <strong>of</strong> cold distilled water <strong>by</strong> keeping the<br />

flasks on a rotary shaker for 1 h at 200 rpm. The mixture was filtered through muslin cloth<br />

and the filtrate was centrifuged at 10000 rpm for 20 min at 4°C and served as crude enzyme<br />

preparation. The volume <strong>of</strong> all the enzyme extracts obtained from the different protocols was<br />

restored to 50 ml <strong>by</strong> cold distilled water and served as the crude enzyme preparation.<br />

<strong>Tannase</strong> and protein assays<br />

The activity <strong>of</strong> tannase was estimated according to the method <strong>of</strong> Mondal [41] where<br />

0.5 ml <strong>of</strong> enzyme solution was incubated with 3 ml <strong>of</strong> 1.0% (w/v) tannic acid, in 0.2 M acetate<br />

buffer (pH 5.0) at 40 °C for 30 min. The reaction was terminated <strong>by</strong> transferring the tubes<br />

containing the reaction mixture to an ice bath followed <strong>by</strong> the addition <strong>of</strong> 2.0 ml (1%, w/v) <strong>of</strong><br />

bovine serum albumin to precipitate the remaining tannic acid. The precipitate was collected <strong>by</strong><br />

centrifugation (12 x 10 3 g for 15 min) and dissolved in 2 ml sodium dodecyl sulphate (SDS)triethanolamine<br />

(1.0%, w/v, SDS in 5% v/v, triethanolamine) solution. Absorbency was<br />

measured at 550 nm 15 min after the addition <strong>of</strong> 1.0 ml <strong>of</strong> FeCl3 (0.13 M dissolved in 0.01 N<br />

HCl). Control treatments were performed using heat-killed enzyme. One unit <strong>of</strong> tannase is the<br />

amount <strong>of</strong> enzyme capable <strong>of</strong> hydrolysing 1.0 mM min -1 <strong>of</strong> tannic acid under the assay<br />

conditions <strong>by</strong> reference to a standard curve constructed with pure tannic acid [41].<br />

Protein content was determined using bovine serum albumin dissolved in 0.17 M<br />

NaCl as a standard [14].<br />

Chemical analyses<br />

Cellulose, hemicellulose and pectin contents <strong>of</strong> F. nitida' leaves were analysed as<br />

described <strong>by</strong> Jermyn [25] and the total nitrogen was estimated <strong>by</strong> the conventional micro-<br />

Kjeldahl method [33, 48].<br />

Tannin was extracted as described <strong>by</strong> Schanderi [55] and estimated as described <strong>by</strong><br />

Lokeswari [35] adopting the Folin–Denis method where a 50 ml aliquot <strong>of</strong> tannin-containing<br />

solution was mixed with 5 ml <strong>of</strong> Folin–Denis reagent, and then 10 ml <strong>of</strong> 15% (w/v) Na2CO3<br />

solution was added and then diluted to the 100 ml mark with distilled water. After thorough<br />

mixing, the flasks were kept in the dark for 30 minutes at 25°C. The absorbency <strong>of</strong> tannin was<br />

measured spectrophotometrically at 700 nm and its concentration calculated using pure tannic<br />

acid as a standard. Distilled water was used as blank regarding the calibration curve. From<br />

this curve, the concentrations for each sample was obtained and used for the tannin content<br />

calculation.<br />

7444 Romanian Biotechnological Letters, Vol. 17, No. 4, 2012


<strong>Economic</strong> <strong>Production</strong> <strong>of</strong> <strong>Tannase</strong> <strong>by</strong> <strong>Aspergillus</strong> <strong>niger</strong> van Tiegh<br />

Adopting Different Fermentation Protocols and Possible Applications<br />

Optimising process parameters for tannase production<br />

Optimising tannase biosynthesis was performed <strong>by</strong> optimizing various physicochemical<br />

process parameters where the optimum condition found for each parameter was<br />

settled for the subsequent experiments. The effect <strong>of</strong> incubation temperature (25 to 45°C) for<br />

different incubation periods (96 to 168 h) at different agitation speeds (125 to 225 rpm) was<br />

explored. Initial pH value <strong>of</strong> the fermentation medium (4 to 7) was adjusted <strong>by</strong> 0.1 M HCl or<br />

NaOH. The effect <strong>of</strong> various initial tannic acid concentrations (2 to 9 g %, w/v) and the<br />

addition <strong>of</strong> various mineral salts i.e. Mg, Ba, Ca, Co, Fe, K, Mn, Na and Zn (added as<br />

chlorides), were also optimised.<br />

Partial purification <strong>of</strong> tannase<br />

Partially purified tannase was prepared as previously described <strong>by</strong> Hamdy [23] where<br />

protein content <strong>of</strong> 500 ml <strong>of</strong> crude tannase <strong>of</strong> A. <strong>niger</strong> was precipitated overnight with 65%<br />

ammonium sulphate, collected <strong>by</strong> centrifugation at 12,000 ×g for 15 min, desalted <strong>by</strong> passing<br />

through a column <strong>of</strong> Sephadex G-25 and then fractionated <strong>by</strong> applying 2 ml to a column<br />

(2.5×82 cm) <strong>of</strong> diethylaminoethyl cellulose (DEAE cellulose, fast flow, fibrous form, Sigma<br />

Chemicals, Germany) for ion-exchange chromatography. 5 ml fractions were eluted with a<br />

linearly increasing molarity <strong>of</strong> NaCl solution (0.0 to 0.5 M) prepared in 0.2-M acetate buffer,<br />

pH 5.0. <strong>Tannase</strong> activity and the protein content <strong>of</strong> each fraction were determined and used to<br />

calculate the corresponding specific activities. Fractions possessing the highest specific<br />

activities were pooled, desalted, lyophilised and used as partially purified tannase in the<br />

experiments <strong>of</strong> reducing tannin.<br />

Application <strong>of</strong> tannase in reducing tannin from tea extract and pomegranate juice<br />

50 g <strong>of</strong> fresh pomegranate seeds were washed with distilled water and extracted in 100<br />

ml distilled water using an electric blender. The extract was filtered through muslin cloth and<br />

kept cooled at 4°C.<br />

Tea extract was prepared <strong>by</strong> adding 2 g <strong>of</strong> locally purchased black tea leaves to 100 ml<br />

<strong>of</strong> boiled distilled water, left to stand for 20 minutes and then kept cold at 4°C.<br />

15 ml <strong>of</strong> the tea or pomegranate juice was incubated with 1 ml <strong>of</strong> partially purified<br />

tannase containing 17.32 U/ mg protein at 30°C for different incubation periods (30 to 150<br />

min) under shaking conditions (150 rpm). Tannin content was determined pre and post<br />

incubation with the enzyme.<br />

Statistical validation <strong>of</strong> treatment effects<br />

The mean, standard deviation, Tukey's test “T” and probability "P" values <strong>of</strong> three<br />

replicates <strong>of</strong> the investigated parameters and the control were calculated according to the<br />

mathematical principles described <strong>by</strong> Glantz [21]. Results were considered highly significant,<br />

significant or non-significant where P < 0.01, > 0.01 and < 0.05, and > 0.05, respectively.<br />

Results and Discussion<br />

Cellulose, hemicelluloses, lignin, pectin, tannin, nitrogen and protein contents <strong>of</strong> Ficus<br />

nitida’ leaves used in the fermentation medium were determined and the results are given in<br />

Table 1. It is known that the detected amounts are subject to dramatic changes according to<br />

genotype, age <strong>of</strong> plant and leaves, soil fertility and acidity, growing season and methods <strong>of</strong><br />

extraction, drying and assay [3].<br />

Romanian Biotechnological Letters, Vol. 17, No. 4, 2012 7445


H. S. HAMDY AND E. M. FAWZY<br />

Table 1: Chemical composition <strong>of</strong> Ficus nitida’ leaves.<br />

Chemical composition (%)<br />

Cellulose 1<br />

Hemicellulose 1<br />

Lignin 1<br />

Pectin 1<br />

Tannin 2<br />

Ash<br />

Nitrogen (N) and protein content 3<br />

32.7 21.93 0.71 11.03 15.01 7.5 0.19 0.83 1.02 6.37<br />

Analyses carried out adopting the methods <strong>of</strong> 1 Jermyn, [25] 2 Lokeswari [35], 3 Pirie, [48] and Lexander [33].<br />

<strong>Aspergillus</strong> <strong>niger</strong> was selected in this study for being classified as GRAS (generally<br />

regarded as safe) and is <strong>of</strong>ficially approved in France for enzyme production for the food<br />

industry [6] where some applications <strong>of</strong> tannase, especially in detanification processes, are<br />

accepted <strong>by</strong> partially purified enzymes [12], which requires a safe source <strong>of</strong> enzyme.<br />

Entrapment in alginate was selected in this study for its highest effectiveness factor (i.e. 1.12<br />

= amounts <strong>of</strong> tannase produced <strong>by</strong> immobilized cells / corresponding amounts produced <strong>by</strong><br />

free cells under the same conditions) versus the other investigated methods, i.e., adsorption to<br />

kieselguhr (0.68), covalent bonding to silica gel beads (0.53) and cross-linking with<br />

glutaraldehyde (0.43). Moreover, alginate gel is characterised <strong>by</strong> its high biodegradability,<br />

hydrophilicity, mechanical stability, rigidity, chemical inertness, ability to bind cells firmly<br />

and high loading capacity [71].<br />

<strong>Tannase</strong> production <strong>by</strong> free or immobilized cells <strong>of</strong> A. <strong>niger</strong> under static or shaking<br />

conditions, adopting LSF, SSF or SlSF was monitored at different temperatures (25 to 45°C)<br />

for different incubation periods (96 to 168 h) in a bifacatorial design. It was found that 30°C<br />

enabled maximum tannase biosynthesis in all cases and the results <strong>of</strong> the time course<br />

production at 30°C are graphically represented in Fig. 1. The optimum temperature for<br />

tannase production <strong>by</strong> most fungal species is around 30°C [10], while tannase production <strong>by</strong><br />

Trichoderma viride [35] has been maximally recorded at 45°C. Decrease in tannase<br />

biosynthesis <strong>by</strong> A. <strong>niger</strong> above 30°C is in agreement with other findings, such as the sharp<br />

decrease in tannase production <strong>by</strong> A. oryzae and almost no tannase production was detected at<br />

40°C [32].<br />

The results <strong>of</strong> time course <strong>of</strong> tannase production <strong>by</strong> A. <strong>niger</strong> in LSF (Fig. 1 a), SSF or<br />

SlSF (Fig. 1 b) at 30°C showed that the maximum biosynthesis achieved after 120 h <strong>of</strong><br />

shaking incubation, and 144 h <strong>of</strong> static incubation. <strong>Production</strong> under shaking conditions was<br />

significantly higher than the static one within the same fermentation protocol. The increased<br />

order <strong>of</strong> enzyme production in relation to different fermentation protocols is as per the<br />

following sequence: SSF (81.5 U 50 ml<br />

7446 Romanian Biotechnological Letters, Vol. 17, No. 4, 2012<br />

-1 ) > Immobilised LSF (77.5 U 50 ml -1 ) > SlF (75.5 U<br />

50 ml -1 ) > Free LSF (69.5 U 50 ml -1 ) (Fig. 1). Therefore, the next stage <strong>of</strong> experiments<br />

focused on the first three for their significant level <strong>of</strong> production as well as representing the<br />

various fermentation protocols. It has been previously found that tannase production <strong>by</strong> A.<br />

<strong>niger</strong> on solid substrates is higher than in LSF (2), where tannase in LSF is partially<br />

intracellular and subsequently secreted into the medium during fermentation, while the<br />

enzyme in SSF is completely secreted out <strong>of</strong> the cells [31]. On the other hand, Srivastava and<br />

Kar [59] stated that extracellular tannase <strong>of</strong> A. <strong>niger</strong> was optimally produced in submerged<br />

cultures. Our results (Fig. 1 a) also showed that tannase biosynthesis <strong>by</strong> immobilized cells <strong>of</strong><br />

A. <strong>niger</strong> in either shaking (77.5 U 50ml -1 ) or static (66 U 50 ml -1 ) conditions was significantly<br />

Soluble N<br />

Insoluble N<br />

Total N<br />

Total protein


<strong>Economic</strong> <strong>Production</strong> <strong>of</strong> <strong>Tannase</strong> <strong>by</strong> <strong>Aspergillus</strong> <strong>niger</strong> van Tiegh<br />

Adopting Different Fermentation Protocols and Possible Applications<br />

higher (P < 0.01) than that <strong>by</strong> free cells (69.5 & 52.5 U 50 ml -1 , in order). Higher amounts <strong>of</strong><br />

tannase production <strong>by</strong> immobilised cells <strong>of</strong> A. <strong>niger</strong> and Bacillus licheniformis KBR6<br />

compared to free cells have also been reported [17, 40].<br />

a- LSF<br />

b- SSF and SlSF<br />

Fig. 1. Time course <strong>of</strong> tannase production <strong>by</strong> A. <strong>niger</strong> at different incubation periods adopting (a) liquid state<br />

(LSF), (b) solid state (SSF) and slurry state (SlSF) fermentation protocols using crude tannic acid extract and F.<br />

nitida leaves, respectively.<br />

Cultures were incubated for the indicated incubation periods while pH was initially<br />

Adjusted to 5.5 and the velocity <strong>of</strong> shaking, if applied, was 150 rpm.<br />

The data represent the mean <strong>of</strong> 3 different readings and the error bars represent the standard deviation <strong>of</strong> means.<br />

<strong>Tannase</strong> biosynthesis in LSF <strong>by</strong> A. flavus has been maximally recorded after 96 h<br />

[45]; while in SSF P. atramentosum has been maximally recorded after 96 h [56]; A. <strong>niger</strong><br />

Romanian Biotechnological Letters, Vol. 17, No. 4, 2012 7447


H. S. HAMDY AND E. M. FAWZY<br />

after 96 h [32], A. <strong>niger</strong> [19], and Paecilomyces variotii, [7] after 120 h; and after 144 h for A.<br />

<strong>niger</strong> ATCC 16620, [54]. Comparison <strong>of</strong> the incubation periods should be undertaken<br />

cautiously even for the same fungal species due to the variation in state <strong>of</strong> the fermentation<br />

and substrate utilised. The recorded decreases in tannase biosynthesis with prolonged<br />

incubation (Fig 1 a & b) could be explained <strong>by</strong> substrate scarcity in the medium, a shift in the<br />

reaction equilibrium due to accumulation <strong>of</strong> gallic acid [27] or an accumulation <strong>of</strong> toxic<br />

metabolities in the fermentation medium.<br />

The effect <strong>of</strong> shaking velocity on tannase production <strong>by</strong> A. <strong>niger</strong> was evaluated and<br />

the maximum yield was obtained at 175 rpm for SSF (89.93 U / 50 ml) and SlSF (88.76 U /<br />

50 ml), while 200 rpm was the optimum (86.76 U/50 ml) for LSF inoculated with<br />

immobilized cells (Fig. 2). A concurrent increase in tannase biosynthesis with an increase in<br />

shaking velocity could be due to the enhancement effect <strong>of</strong> shaking on heat, mass and oxygen<br />

transfer capabilities in the fermentation media that minimizes moisture loss and drying in SSF<br />

[27] and overcomes a serious constraint to high enzyme productivity <strong>by</strong> immobilized aerobic<br />

cells where most <strong>of</strong> the interiors <strong>of</strong> large beads may be anaerobic [60]. On the other hand, a<br />

decline in tannase biosynthesis as the velocity <strong>of</strong> shaking increases above the optimum level<br />

could be ascribed to increasing the frequency <strong>of</strong> particle tumbling that disrupts the mycelium<br />

in the early growth stages [36], thus increasing vaculoation <strong>of</strong> older hyphal compartments and<br />

leading to autolysis or weakened hyphae [47] and/or making the mycelium easier to peel <strong>of</strong>f<br />

from the substrate surface [61]. A decrease in enzyme biosynthesis at higher rotation speeds<br />

was more pronounced in SSF and SlSF than in LSF using immobilised cells where the curve<br />

was broader (Fig. 2), most probably, due to the known protective effect <strong>of</strong> the immobilisation<br />

on cells.<br />

Fig. 2. Effect <strong>of</strong> shaking velocity on tannase production <strong>by</strong> A. <strong>niger</strong> after 120 h <strong>of</strong> incubation at 30°C, in the<br />

different fermentation protocols (LSF __ ♦ __ , inoculated with immobilized cells <strong>of</strong> A. <strong>niger</strong>; SSF __ ■ __ and<br />

SlSF __ ▲ __ inoculated with free cells <strong>of</strong> A. <strong>niger</strong> and grown on leaves <strong>of</strong> F. nitida) at the indicated velocity <strong>of</strong><br />

shaking. Initial pH <strong>of</strong> the medium was adjusted to 5.5.<br />

7448 Romanian Biotechnological Letters, Vol. 17, No. 4, 2012


<strong>Economic</strong> <strong>Production</strong> <strong>of</strong> <strong>Tannase</strong> <strong>by</strong> <strong>Aspergillus</strong> <strong>niger</strong> van Tiegh<br />

Adopting Different Fermentation Protocols and Possible Applications<br />

Maximum tannase production <strong>by</strong> A. <strong>niger</strong> (96.11, 114.76, 106.8 U 50 ml -1 for LSF,<br />

SSF, SlSF in order) was optimally recorded at an initial pH <strong>of</strong> 5.0 <strong>of</strong> the fermentation medium<br />

(Fig. 3). Applying different fermentation protocols have so far not been found to shift the<br />

optimum pH value, where a range <strong>of</strong> 4.5 to 6.5 enabled maximum tannase production <strong>by</strong> A.<br />

flavus, A. foetidus, A. japonicus, A. <strong>niger</strong>, A. oryzae, Paecilomyces variotti, Penicillium<br />

atramentosum, P. chrysogenum, grown on tannery solid substrates or in submerged media [1,<br />

6, 7, 27, 50, 56]. It is known that biological surfaces consist <strong>of</strong> different functional groups<br />

that become dissociated if the pH is above a certain value [71]. As shown in Fig. 3, the curve<br />

<strong>of</strong> tannase synthesis in LSF is broader, where a decline in tannase synthesis is lower and the<br />

active pH range is wider than that in SSF and SlSF.<br />

Fig. 3. pH-dependency <strong>of</strong> tannase production <strong>by</strong> A. <strong>niger</strong> after 120 h <strong>of</strong> shaking incubation at 30°C in different<br />

fermentation protocols (LSF __ ♦ __ , 200 rpm, inoculated with immobilised cells <strong>of</strong> A. <strong>niger</strong>;SSF __ ■ __ , and<br />

SlSF __ ▲ __ , 175 rpm, inoculated with free cells <strong>of</strong> A. <strong>niger</strong> and grown on leaves <strong>of</strong> F. nitida). Initial pH <strong>of</strong> the<br />

medium was adjusted using 0.1 M HCl or NaOH.<br />

The effect <strong>of</strong> initial tannin concentration on production <strong>of</strong> tannase <strong>by</strong> A. <strong>niger</strong> was<br />

studied and the results showed that maximum productivity was attained at 7% (w/v) in both<br />

LSF (146.10 U 50 ml -1 ) and SSF (190.50 U 50 ml -1 ) and at 6% in SlSF (153.72 U 50 ml -1 ),<br />

representing an increase in production <strong>of</strong> 1.88, 2.34 and 2.04-fold, respectively (Table 2).<br />

Tannin concentration is an important detrimental factor in microbial production <strong>of</strong> tannase<br />

and its optimum concentration for A. <strong>niger</strong> has been recorded at 4%, 5% and 10% <strong>by</strong> Lekha<br />

and Lonsane [31, 32], Aguilar [2] and Sharma [58], respectively, while various concentrations<br />

ranging from 0.5 to 10% have been recorded for other fungal species [10]. A reduction in the<br />

tannase yield at higher concentrations <strong>of</strong> tannin could be due to its toxic effect where it forms<br />

non-reversible bonds with surface proteins <strong>of</strong> the organism [5], deposition <strong>of</strong> gallic acid on<br />

cell surfaces [57], as well as depriving metal ions and substrates on membranes [13, 52] that<br />

impair metabolism, inhibit the organism and decrease tannase production. The ability <strong>of</strong><br />

several fungi to grow and tolerate relatively high tannin concentrations <strong>of</strong> up to 20%, as in A.<br />

<strong>niger</strong> [22], is an advantage for fungi as tannase producers.<br />

Romanian Biotechnological Letters, Vol. 17, No. 4, 2012 7449


H. S. HAMDY AND E. M. FAWZY<br />

Table 2: The effect <strong>of</strong> varying initial crude tannin concentration on tannase production <strong>by</strong> A. <strong>niger</strong> in different<br />

fermentation protocols.<br />

Crude<br />

<strong>Tannase</strong> productivity<br />

tannin<br />

conc. (%)<br />

*<br />

LSF 1 SSF 2 SlSF 3<br />

U 50 ml -1<br />

% U 50 ml -1<br />

% U 50 ml -1 %<br />

3 (control) 96.11 ± 2.21 100 114.76 * ± 4.36 100 109.80 ± 2.74 100<br />

4 123.00 * ± 3.93 128 161.81 * ± 5.17 141 132.86 * ± 4.51 121<br />

5 131.67 * ± 5.13 137 174.43 * ± 6.27 152 133.95 * ± 4.28 122<br />

6 138.39 * ± 2.90 144 182.47 * ± 4.01 159 153.72 * ± 4.45 140<br />

7 146.10 * ± 6.28 152 190.50 * ± 5.90 166 142.74 * ± 5.42 130<br />

8 143.20 * ± 2.72 149 183.62 * ± 7.52 160 131.76 * ± 5.13 120<br />

9 131.67 * ± 3.42 137 161.81 * ± 4.20 141 117.49 * ± 2.70 107<br />

Initial pH <strong>of</strong> the fermentation medium was adjusted to 5.0, and incubated at 30ºC for 120 h with shacking<br />

incubation at: 200 rpm for LSF and 175 rpm for SSF and SlSF.<br />

1 Liquid state fermentation using crude tannic acid extract and inoculated with immobilised A. <strong>niger</strong> cell.<br />

2 , 3 Solid-state and slurry-state fermentations using F. nitida and inoculated with free cells <strong>of</strong> A. <strong>niger</strong>. 10 g <strong>of</strong><br />

dried F. nitida’ leaves (15% tannin on dry weight base –Table 1- that equals 3% w/v in the fermentation<br />

medium) were used and higher tannin concentrations were applied to the liquid part <strong>of</strong> the medium.<br />

Significance <strong>of</strong> results was statistically validated compared to the control (3% crude tannin concentration)<br />

where * indicates highly significant difference.<br />

The effect <strong>of</strong> adding different metal ions at concentrations <strong>of</strong> 0.1, 0.2 and 0.3 g % (w/v)<br />

to the fermentation media was investigated and the results showed that tannase production<br />

was stimulated in the following descending order: Ca<br />

7450 Romanian Biotechnological Letters, Vol. 17, No. 4, 2012<br />

2+ , Mg 2+ , Mn 2+ , Zn 2+ in LSF and SSF,<br />

and Ca 2+ , Mn 2+ , Mg 2+ , Zn 2+ in SlSF (Table 3). It has been established that metal ions<br />

significantly affect the progress and efficiency <strong>of</strong> fermentation, secretion <strong>of</strong> active enzymes<br />

and synthesis <strong>of</strong> secondary metabolites <strong>by</strong> microorganisms and their ability to attach to their<br />

various substrates [38] <strong>by</strong> affecting the dynamics <strong>of</strong> cell membranes, cell viability,<br />

permeability, membrane fluidity, stability and signalling systems [30]. <strong>Tannase</strong> synthesis <strong>by</strong><br />

A. foetidus, A. japonicas A. <strong>niger</strong> A. oryzae, A. pullulans and R. oryzae are also stimulated <strong>by</strong><br />

Ca 2+ , Mg 2+ , Mn 2+ and Zn 2+ [1, 4, 8, 28, 62], while tannase synthesis <strong>by</strong> A. <strong>niger</strong> [6] and P.<br />

chrysogenum [50] is inhibited <strong>by</strong> Zn +2 . On the other hand, in the present investigation,<br />

tannase synthesis <strong>by</strong> A. <strong>niger</strong> was inhibited in the following descending order: Ba 2+ , Co 2+ ,<br />

Fe 2+ in LSF and Co 2+ , Ba 2+ and Fe 2+ in SSF and SlSF. Ba 2+ and Co 2+ also inhibit tannase<br />

synthesis <strong>by</strong> A. <strong>niger</strong> and A. pullulans [4]. Inhibition mediated <strong>by</strong> Fe 2+ is in agreement with<br />

the results <strong>of</strong> Rajakumar and Nandy [50] and Barthom<strong>eu</strong>f [6] on tannase synthesis <strong>by</strong> A.<br />

<strong>niger</strong>, A. pullulans and P. chrysogenum but disagree with those <strong>of</strong> Banerjee [4] and Trevino-<br />

Cueto [62] on tannase synthesised <strong>by</strong> A. aculeatus and A. <strong>niger</strong>, respectively. The presence <strong>of</strong><br />

some metal ions in the fermentation medium may inhibit tannase synthesis due to their<br />

binding with tannic acid to form insoluble complexes, hence, limiting its bioavailability as a<br />

carbon source and inducer for enzyme synthesis [22]. This assumption was excluded in the<br />

present study where raising the level <strong>of</strong> tannin concentration in the fermentation medium<br />

containing the inhibitory metal salts (i.e. Ba 2+ , Co 2+ , or Fe 2+ ) did not show a significant<br />

enhancement effect on tannase synthesis (P > 0.05, data not shown). On the other hand,<br />

possible inhibition due to the binding <strong>of</strong> tannic acid to metal ions affecting the metal<br />

bioavailability, which in turn affects efficiencies <strong>of</strong> metabolic processes, secretion <strong>of</strong> active<br />

enzymes and the ability <strong>of</strong> the microorganisms to attach to their various substrates [38], was<br />

also ruled out since inhibition <strong>of</strong> tannase synthesis <strong>by</strong> A. <strong>niger</strong> was more pronounced at higher<br />

concentrations <strong>of</strong> Ba 2+ , Co 2+ or Fe 2+ (Table 3). The previous discussion suggests that the<br />

effect <strong>of</strong> metals is, most probably, on the activity <strong>of</strong> the secreted tannase rather than on<br />

tannase synthesis itself, consequently affecting the ability <strong>of</strong> A. <strong>niger</strong> to utilize the available<br />

tannin in the medium. Moreover, reduction in tannase productivity at higher concentrations


<strong>Economic</strong> <strong>Production</strong> <strong>of</strong> <strong>Tannase</strong> <strong>by</strong> <strong>Aspergillus</strong> <strong>niger</strong> van Tiegh<br />

Adopting Different Fermentation Protocols and Possible Applications<br />

<strong>of</strong> metal ions could be due to the partial denaturation <strong>of</strong> some other important enzymes<br />

because <strong>of</strong> the presence <strong>of</strong> excessive free ions in the media [63], nonspecific binding or<br />

aggregation <strong>of</strong> the enzyme [28] or possible osmotic stress on the cells.<br />

Table 3: Effect <strong>of</strong> different metal salts at different concentrations on tannase production <strong>by</strong> A. <strong>niger</strong> in different<br />

fermentation protocols.<br />

Metal<br />

salt<br />

BaCl2<br />

CaCl2<br />

CoCl2<br />

FeCl2<br />

KCl<br />

MnCl<br />

MgCl2<br />

NaCl<br />

ZnCl2<br />

2<br />

Conc.<br />

(g %,<br />

w/v)<br />

<strong>Tannase</strong> productivity (U 50 ml -1 )<br />

LSF 1 SSF 2 SlSF 3<br />

0.1 60.8 ± 2.37 * 167.64 ± 5.69 * 107.60 ± 4.41 *<br />

0.2 53.2 ± 1.17 * 146.68 ± 3.81 * 83.00 ± 2.15 *<br />

0.3 41.04 ± 0.98 * 131.44 ± 4.86 * 56.87 ± 1.42 *<br />

0.1 296.4 ± 9.18 * 321.94 ± 13.19 * 265.93 ± 9.04 *<br />

0.2 278.16 ± 5.28 * 280.03 ± 8.68 * 232.11 ± 7.42 *<br />

0.3 264.48 ± 11.37 * 253.36 ± 7.34 * 222.89 ± 6.46 *<br />

0.1 136.8 ± 3.83 * 62.865 ± 2.01 * 75.32 ± 2.86 *<br />

0.2 63.84 ± 2.17 * 59.05 ± 2.24 * 58.41 ± 2.27 *<br />

0.3 57.76 ± 2.02 * 36.19 ± 0.83 * 39.96 ± 0.91 *<br />

0.1 141.36 ± 4.09 * 173.35 ± 5.37 * 115.29 ± 3.22 *<br />

0.2 133.76 ± 4.14 * 152.4 ± 5.18 * 107.60 ± 4.19 *<br />

0.3 110.96 ± 4.32 * 133.35 ± 4.26 * 93.77 ± 3.46 *<br />

0.1 151.24 ± 5.44 n 190.5 ± 5.52 n 152.18 ± 5.02 n<br />

0.2 152 ± 4.25 n 192.40 ± 7.50 n 158.33 ± 3.64 n<br />

0.3 155.04 ± 3.25 n 203.84 ± 7.94 156.79 ± 3.29 n<br />

0.1 121.6 ± 4.37 * 169.54 ± 6.61 * 138.35 ± 4.98 *<br />

0.2• 152 ± 5.77 190.5 ± 4.95 153.72 ± 3.38<br />

0.3 232.56 ± 6.27 * 276.23 ± 9.11 * 182.93 ± 5.67 *<br />

0.1 200.64 ± 7.42 * 234.31 ± 5.38 * 201.37 ± 6.24 *<br />

0.2 205.2 ± 3.89 * 262.89 ± 8.41 * 204.45 ± 4.49 *<br />

0.3 212.8 ± 5.32 * 266.7 ± 10.40 * 216.74 ± 9.31 *<br />

0.1 152 ± 4.86 n 190.5 ± 4.00 n 146.03 ± 4.23 **<br />

0.2 165.68 ± 6.79 * 190.5 ± 8.19 n 139.88 ± 4.89 *<br />

0.3 167.2 ± 6.35 * 190.5 ± 3.61 n 138.35 ± 4.70 *<br />

0.1 183.92 ± 5.70 * 211.45 ± 5.49 * 178.32 ± 4.27 *<br />

0.2 196.08 ± 4.50 * 190.5 ± 7.23 n 184.46 ± 7.93 *<br />

0.3 183.92 ± 5.88 * 188.95 ± 6.04 n 179.85 ± 3.95 *<br />

* = highly significant (P < 0.01), ** = significant (P > 0.01 and < 0.05) and n = non significant (P > 0.05) in<br />

comparison to • Control (i.e., the original fermentation medium).<br />

1 Liquid-state fermentation inoculated with immobilised cells <strong>of</strong> A. <strong>niger</strong> and grown on 7 % crude tannic acid<br />

extract at 30°C, 200 rpm, and 2 , 3 Solid-state and slurry-state fermentations using F. nitida and inoculated with<br />

free cells <strong>of</strong> A. <strong>niger</strong>.<br />

The investigated metal salts were separately added at the indicated concentrations to the fermentation media. No<br />

growth was determined in the presence <strong>of</strong> HgCl2 or PbCl2. Initial pH was adjusted to 5 with ammonium<br />

hydroxide instead <strong>of</strong> NaOH to prevent the interference from sodium ions.<br />

The effect <strong>of</strong> adding all the possible combinations <strong>of</strong> Mg 2+ , Ca 2+ , Mn 2+ and Zn 2+ ,<br />

considered as stimulators <strong>of</strong> tannase biosynthesis <strong>by</strong> A. <strong>niger</strong>, to the fermentation media was<br />

investigated and the results showed that any such combination enhanced the levels <strong>of</strong> tannase<br />

synthesis at variable significant levels (Table 4). The maximum stimulatory effect was<br />

Romanian Biotechnological Letters, Vol. 17, No. 4, 2012 7451


H. S. HAMDY AND E. M. FAWZY<br />

attained in the presence <strong>of</strong> Mg 2+ , Ca 2+ , Mn 2+ and Zn 2+ with a 2.9 (451 U 50 ml -1 ), 2.4 (457.2<br />

U 50 ml -1 ) and 2.1 (324.3 U 50 ml -1 ) fold increment in tannase synthesis in LSF, SSF and<br />

SlSF, respectively. Optimising the mineral nutrition requirements in the fermentation media<br />

for tannase synthesis <strong>by</strong> different microorganisms enhanced the yield at different levels, i.e.,<br />

<strong>by</strong> 2.8 (A. aculeatus), and 1.9 (A. pullulans) fold [4] and 4 fold in the case <strong>of</strong> B. licheniformis<br />

[39]. The exerted stimulatory effect <strong>of</strong> the combinations <strong>of</strong> metallic salts on tannase synthesis<br />

<strong>by</strong> A. <strong>niger</strong> is the net result <strong>of</strong> the interactions between the available metals either in a<br />

synergetic or antagonistic manner. For example, a balanced mixture <strong>of</strong> K 2+ and Mg 2+ salts<br />

enhances tannase synthesis <strong>by</strong> B. licheniformis [39] while the stimulatory effect <strong>of</strong> Ca 2+ on<br />

tannase production <strong>by</strong> yeasts declines at higher concentrations due to the known antagonistic<br />

effect <strong>of</strong> calcium on magnesium uptake and its consequent effect on some essential magnesiumdependent<br />

metabolic processes [66]. Moreover, the known depressive effect <strong>of</strong> Mn 2+ on<br />

respiration, nucleic acid synthesis and proteins synthesis can be antagonised <strong>by</strong> Ca 2+ [70].<br />

Repeated batch culture<br />

The efficiency <strong>of</strong> the immobilised A. <strong>niger</strong> for tannase production in a repeated batch<br />

process was evaluated in 250 ml Erlenmeyer flasks and the productivity over 7 cycles is given<br />

in Fig. 4. Significant amounts <strong>of</strong> tannase were produced up to the 5 th cycle (266.54 U 50 ml -1 ,<br />

representing 59% <strong>of</strong> the production at the 1 st cycle), while almost stable amounts were<br />

produced during the first 3 cycles. In this respect, immobilised cultures <strong>of</strong> A. <strong>niger</strong> have<br />

exhibited significant tannase production stability <strong>of</strong> two repeated runs [17], while tannase<br />

production <strong>by</strong> immobilised cells <strong>of</strong> B. licheniformis have been demonstrated to be successful<br />

for up to 13 cycles, with its maximum level being reached at the 3 rd cycle [40].<br />

Table 4: The effect <strong>of</strong> adding different mixtures <strong>of</strong> metal salts on tannase production <strong>by</strong> A. <strong>niger</strong> in different<br />

fermentation protocols<br />

Minerals 1<br />

<strong>Tannase</strong> productivity (U 50 ml -1 LSF<br />

)<br />

SSF SlSF<br />

(Original Medium) Control 152 190.5 153.7 (100)<br />

Ca 2+ 296.4 ± 8.00 * 321.95 ± 12.55 * 265.90 ± 5.84 *<br />

Mg 2+ 232.56 ± 6.97 * 276.23 ± 9.94 * 182.90 ± 6.95 *<br />

Mn 2+ 212.8 ± 5.10 * 266.7 ± 8.26 * 216.72 ± 4.11 *<br />

Zn 2+ 196.1 ± 8.43 * 211.46 ± 5.92 * 184.44 ± 6.27 *<br />

Ca 2+ + Mg 2+ 375.44 ± 13.14 * 329.56 ± 9.55 * 276.66 ± 8.57 *<br />

Ca 2+ + Mn 2+ 320.72 ± 8.02 * 346.71 ± 11.09 * 290.49 ± 11.91 *<br />

Ca 2+ + Zn 2+ 314.64 ± 11.95 * 323.85 ± 10.03 * 272.05 ± 6.25 *<br />

Mg 2+ + Mn 2+ 264.48 ± 10.31 * 304.8 ± 10.97 * 233.62 ± 6.54 *<br />

Mg 2+ + Zn 2+ 255.36 ± 5.36 * 297.18 ± 10.99 * 210.57 ± 4.00 *<br />

Mn 2+ + Zn 2+ 258.4 ± 9.30 * 291.47 ± 11.07 * 230.55 ± 6.22 *<br />

Ca 2+ + Mg 2+ + Mn 2+ 351.12 ± 13.69 * 379.10 ± 8.34 * 282.81 ± 6.78 *<br />

Ca 2+ + Mg 2+ + Zn 2+ 319.2 ± 9.89 * 342.9 ± 6.51 * 276.66 ± 11.89 *<br />

Ca 2+ + Mn 2+ + Zn 2+ 349.6 ± 10.13 * 375.29 ± 11.63 * 305.86 ± 11.92 *<br />

Mg 2+ + Mn 2+ + Zn 2+ 270.56 ± 7.57 * 302.90 ± 10.29 * 233.62 ± 8.17 *<br />

Ca 2+ + Mg 2+ + Mn 2+ + Zn 2+ 451.44 ± 16.25 * 457.2 ± 12.80 * 324.31 ± 10.54 *<br />

1<br />

Added at the optimum concentration enabled maximum tannase synthesis shown in Table 3<br />

*<br />

highly significant (P < 0.01) in comparison to control<br />

Significant production over repeated cycles could be due to long term cell viability,<br />

reducing the damage <strong>of</strong> fungal mycelia and continuous metabolic activities that are known to<br />

be advantages for immobilised cells [17]. The observed decrease in enzyme productivity after<br />

several cycles could be attributable to the high growth <strong>of</strong> biomass, increasing cell density<br />

7452 Romanian Biotechnological Letters, Vol. 17, No. 4, 2012


<strong>Economic</strong> <strong>Production</strong> <strong>of</strong> <strong>Tannase</strong> <strong>by</strong> <strong>Aspergillus</strong> <strong>niger</strong> van Tiegh<br />

Adopting Different Fermentation Protocols and Possible Applications<br />

and/or the presence <strong>of</strong> dead cells that cause diffusional limitation <strong>of</strong> oxygen, substrate and<br />

product inside and out <strong>of</strong> the beads, in addition to the mass transfer limitation that is still the<br />

major drawback in the application <strong>of</strong> an entrapment technique [68].<br />

Total activity (U / 50 ml)<br />

500<br />

400<br />

300<br />

200<br />

100<br />

0<br />

1 2 3 4 5 6 7<br />

Number <strong>of</strong> cycle<br />

Fig. 4. Repeated batch culture for tannase production using immobilised cells <strong>of</strong> A. <strong>niger</strong><br />

The presence <strong>of</strong> large amounts <strong>of</strong> tannins in human food and animal forages reduces<br />

the nutritive value [22] and has serious health implications [15]. Biological processes reduce<br />

the antinutritional effects <strong>of</strong> tannin and improve digestibility <strong>by</strong> adopting tannase preparations<br />

or various tannase-producing fungal strains [42]. Meanwhile, the fermentation residue<br />

resulting from SSF for tannase production is an agricultural waste that has already been<br />

detannified and may represent an extra added value if used in animal feed. To this end, tannin<br />

and protein contents <strong>of</strong> the leaves <strong>of</strong> F. nitida were monitored throughout fermentation and<br />

the results are given in Fig. 5 which show that tannin levels reduced <strong>by</strong> 27.33 % after 120 h <strong>of</strong><br />

fermentation. A reduction in tannin content due to fermentation <strong>by</strong> A. oryzae and B.<br />

licheniforms utilising different substrates range from 0.1 %, (Psidium guazava), 20 to 35%<br />

(Acacia auriculiformis, Casuarina equisetifolia and Delonix regia); and up to 53 to 75%<br />

(Anacardium occidentale, Cassia fistula, Eucalyptus tereticornis, and Ficus benghalensis)<br />

[34, 39]. Meanwhile, 90% <strong>of</strong> the tannin content <strong>of</strong> creosote bush plant materials is degraded<br />

<strong>by</strong> A. <strong>niger</strong> [9]. Such variations in tannin biodegradation and digestibility depend on the<br />

nature <strong>of</strong> leaves, fungi and fermentation times. The residual amount <strong>of</strong> tannin in the<br />

fermentation residue <strong>of</strong> F. nitida (10.90 %) might benefit ruminants <strong>by</strong> protecting proteins<br />

from microbial deamination and preventing bloats [22]. Meanwhile, in the present study, the<br />

protein content <strong>of</strong> F. nitida leaves increased <strong>by</strong> 24.33 % after 120 h <strong>of</strong> incubation before<br />

decreasing (Fig 5). This decrease in tannase biosynthesis could be because <strong>of</strong> changes in the<br />

prevailing conditions and physiology <strong>of</strong> the fungus where protein serves as a substrate. The<br />

protein content <strong>of</strong> creosote bush (Larrea tridentata) and tar bush (Flourensia cernua) used in<br />

SSF for tannase production <strong>by</strong> A. <strong>niger</strong> PSH and GH1 has been shown to increase <strong>by</strong> 30% and<br />

11 %, and 0.62%, 0.76%, respectively [9].<br />

Romanian Biotechnological Letters, Vol. 17, No. 4, 2012 7453


Total protein (%)<br />

10<br />

8<br />

Total tannin (%)<br />

6<br />

4<br />

2<br />

0<br />

H. S. HAMDY AND E. M. FAWZY<br />

Total Protein (%) Tannin (%)<br />

0 24 48 72 96 120 144<br />

Incubation time (h)<br />

Fig. 5: Changes in tannin and protein contents <strong>of</strong> the fermented F. nitida' leaves used for the production <strong>of</strong><br />

tannase <strong>by</strong> A. <strong>niger</strong>.<br />

Possible applications <strong>of</strong> the partially purified tannase produced <strong>by</strong> A. <strong>niger</strong> was<br />

investigated <strong>by</strong> reducing tannin levels in tea extract and pomegranate juice. 55% <strong>of</strong> tannin<br />

was hydrolysed after 30 minutes <strong>of</strong> treating tea extract with A. <strong>niger</strong> tannase, while 45 % was<br />

removed from pomegranate juice after 120 minutes (Table 5). <strong>Tannase</strong> from P.<br />

atramentosum has been shown to reduce 38% <strong>of</strong> jamum wine; 43.5% <strong>of</strong> grape wine and 74%<br />

<strong>of</strong> tea extract after 3 h at 35° C [56] while 25% <strong>of</strong> tannin content <strong>of</strong> pomegranate juice has<br />

been reported to be reduced [53].<br />

Table (5): Hydrolysis <strong>of</strong> tannin content <strong>of</strong> tea extract and pomegranate juice with treatment <strong>of</strong> partially purified<br />

tannase from A. <strong>niger</strong><br />

Incubation time<br />

(Minutes)<br />

7454 Romanian Biotechnological Letters, Vol. 17, No. 4, 2012<br />

20<br />

15<br />

10<br />

% Tannin hydrolysis<br />

Tea extract Pomegranate<br />

0 100 % (175.12 µg ml -1 ) 100 % (975 µg ml -1 )<br />

30 22 17<br />

60 29 21<br />

90 38 32<br />

120 55 45<br />

150 55 44<br />

1 ml <strong>of</strong> the partially purified tannase containing 17.32 U/ mg protein was incubated at 30° C in a rotary<br />

shaker (150 rpm) with 15 ml <strong>of</strong> tea extract or pome granate juice at pH 5 for the indicated time periods.<br />

Concluding remarks<br />

In the present work, we report for the first time the production <strong>of</strong> tannase <strong>by</strong> A. <strong>niger</strong><br />

using F. nitida leaves and crude tannic acid extract as a cost-effective alternative to largescale<br />

production where pure tannic acid is a very costly substrate. The optimum temperature<br />

for tannase production was recorded at 30°C, indicating A. <strong>niger</strong> as a suitable candidate for<br />

5<br />

0


<strong>Economic</strong> <strong>Production</strong> <strong>of</strong> <strong>Tannase</strong> <strong>by</strong> <strong>Aspergillus</strong> <strong>niger</strong> van Tiegh<br />

Adopting Different Fermentation Protocols and Possible Applications<br />

tannase production at room temperature using F. nitida leaves in tropical countries such as<br />

Egypt with minor control processes where much <strong>of</strong> the necessary energy cost can be reduced.<br />

Parameters <strong>of</strong> tannase production (incubation period, incubation temperature, shaking<br />

velocity, initial pH, initial tannic acid concentration and mineral nutritional requirements)<br />

were optimised and increased production <strong>by</strong> 5.82, 5.61, and 4.29 fold in LSF, SSF, SlSF,<br />

respectively. Moreover, suitability <strong>of</strong> the SSF residue as a candidate for animal feed is<br />

suggested for further research. We also demonstrated the potentiality <strong>of</strong> the partially purified<br />

tannase for application in the removal <strong>of</strong> tannin from tea extract and pomegranate juice.<br />

References<br />

1. M. A. ABDEL-NABEY, A. A. SHERIEF, A. B. EL-TANASH, Tannin biodegradation and some<br />

factors affecting <strong>Tannase</strong> production <strong>by</strong> two <strong>Aspergillus</strong> sp. Biotechnology. 10(2): 149-158 (2011).<br />

2. C. N.AGUILAR, C. AUGUR, E. FAVELA, Z. VINIEGRA-GONZALEZ, <strong>Production</strong> <strong>of</strong> tannase <strong>by</strong><br />

<strong>Aspergillus</strong> <strong>niger</strong> Aa-20 in submerged and solid-state fermentation: influence <strong>of</strong> glucose and tannic<br />

acid. J. Ind. Microbiol. Biotechnol. 26: 296-302 (2001).<br />

3. I. T. BALDWIN, J. C. SCHULTZ, D. WARD, Patterns and sources <strong>of</strong> leaf tannin variation in yellow<br />

birch (Betula allegheniensis) and sugar maple (Acer saccharum). J. Chem. Ecol. 13, 1069-1078 (1987).<br />

4. S. D. BANERJEE, Microbial production <strong>of</strong> tannase and gallic acid. Ph. D. Thesis, Vidyasagar<br />

University, India. (2005).<br />

5. D. Banerjee, K.C. Mondal, B.R. Pati <strong>Tannase</strong> production <strong>by</strong> <strong>Aspergillus</strong> aculeatus DBF9 through solidstate<br />

fermentation. Acta Microbiol Immunol Hung; 54(2):159-66 (2007).<br />

6. C. BARTHOMEUF, F. Regerat, H. Pourrat, <strong>Production</strong>, purification and characterization <strong>of</strong> a tannase<br />

from A. <strong>niger</strong> LCF8. J. Ferment. Bioeng. 77(3): 320-323 (1994).<br />

7. V. BATTESTIN, G.A. MACEDO, Effects <strong>of</strong> temperature, pH and additives on the activity <strong>of</strong> tannase<br />

produced <strong>by</strong> Paecilomyces variotii. Elec. J. Biotechnol. Vol. 10(2): 191 -199 (2007).<br />

8. R. BELMARES, J.C. CONTRERAS-ESQUIVEL, R. RODRÍGUEZ- HERRERA, A. RAMÍREZ-<br />

CORONEL, C.N. AGUILAR, Microbial production <strong>of</strong> tannase: an enzyme with potential use in food<br />

industry. Lebensm. Wiss. U.- Technol. 37: pp. 857 – 864 (2004).<br />

9. R. BELMARES, Y. GARZA, R. RODRÍGUEZ, J. CONTRERAS-ESQUIVEL, C. Aguilar,<br />

Composition and fungal degradation <strong>of</strong> tannins present in semiarid plants. Electronic J. Environ. Agric.<br />

Food Chem. 8(7), 512-518 (2009).<br />

10. P. D. BELUR, G. MUGERAYA, Microbial production <strong>of</strong> tannase: State <strong>of</strong> the art. Res. J. Microbiol. 6,<br />

25-40 (2011).<br />

11. V. BENIWAL, V. CHHOKAR, Statistical optimization <strong>of</strong> culture conditions for <strong>Tannase</strong> production <strong>by</strong><br />

<strong>Aspergillus</strong> awamori MTCC 9299 under submerged fermentation. Asian J. Biotechnol. 2(1), 46-52<br />

(2010).<br />

12. R. BHARDWAJ, B. SINGH, T.K. BHAT, Purification and characterization <strong>of</strong> tannin acyl hydrolase<br />

from <strong>Aspergillus</strong> <strong>niger</strong> MTCC 2425. J. Basic Microbiol. 43, 449-461 (2003).<br />

13. T.K. BHAT, H.P. MAKKAR, B. SINGH, Preliminary studies on tannin degradation <strong>by</strong> <strong>Aspergillus</strong><br />

<strong>niger</strong> van Tieghem MTCC 2425. Lett. Appl. Microbiol. 25, 22-23 (1997).<br />

14. M. M. BRADFORD, A Rapid and Sensitive Method for the Quantitation <strong>of</strong> Microgram Quantities <strong>of</strong><br />

Protein Utilizing the Principle <strong>of</strong> Protein-Dye Binding. Anal. Biochem. 72. pp. 248 – 254 (1976).<br />

15. K.T. CHANG, T.Y. WONG, C.I. WEI, Y.W. HUANG, Y. LIN, Tannins and human health: a review.<br />

Crit. Rev. Food Sci. Nutr. 38(6), 421-464 (1998).<br />

16. M. CHAVEZ-GONZALEZ, L.V. RODRIGUEZ-DURAN, N. BALAGURUSAMY, A. PRADO-<br />

BARRAGAN, R. RODRIGUEZ, J. CONTRERAS, C.N. AGUILAR, Biotechnological advances and<br />

challenges <strong>of</strong> tannase: An overview. Food Bioprocess Technol. Published online first. DOI<br />

1001007/s11947-011-0608-5 (2011).<br />

17. I. DARAH, G. SUMATHI, K. JAIN, S.H. LIM, <strong>Tannase</strong> enzyme production <strong>by</strong> entrapped cells <strong>of</strong><br />

<strong>Aspergillus</strong> <strong>niger</strong> FELT FT3 in submerged culture system. Bioprocess Biosyst. Eng. 19(13), 1-7 (2011).<br />

18. A. DE-GREGORIO, G. MANDALARI, N. ARENA, F. NUCITA, M.M. TRIPODO, R.B. Lo CURTO,<br />

SCP and crude pectinase production <strong>by</strong> slurry-state fermentation <strong>of</strong> lemon pulps. Biores. Technol. 83,<br />

89-94 (2002).<br />

19. M.Z. EL-FOULY, Z. EL-AWAMRY, A.M. SHAHIN, H. EL-BIALY, E. NAEEM, G. EL-SAEED,<br />

Biosynthesis and characterization <strong>of</strong> <strong>Aspergillus</strong> <strong>niger</strong> AUMC 4301 tannase. J. American Sci., 6(12), 709-<br />

721 (2010).<br />

Romanian Biotechnological Letters, Vol. 17, No. 4, 2012 7455


H. S. HAMDY AND E. M. FAWZY<br />

20. A. GATHON, Z. GROSS, M. ROZHANSKI, Propyl gallate: enzymatic synthesis in a reverse micelle<br />

system. Enzyme Microb Technol. 11, 604-9 (1989).<br />

21. AS. Glantz, Primer <strong>of</strong> biostatistics. McGraw Hill, Inc., USA. pp. 2-18 (1992).<br />

22. G. Goel, A. Puniya, C. Aguilar, K. Singh, Interaction <strong>of</strong> gut micr<strong>of</strong>lora with tannins in feeds.<br />

Naturwissenschaften, 92(11), 497-503 (2005).<br />

23. H. S. Hamdy, Purification and characterization <strong>of</strong> a newly isolated stable long-life tannase produced <strong>by</strong> F.<br />

subglutinans (Wollenweber and Reinking) Nelson et al. J. Pharm. Innov. 3(3), 142-151 (2008).<br />

24. E. Haslam, J.N. Tanner, Spectrophotometric assay <strong>of</strong> tannase. Phytochem; 90, 2305-2309 (1970).<br />

25. M. A. Jermyn, Cellulose and hemicellulose. In: Peach K., Tracey M. V., Eds., Modern Methods <strong>of</strong> Plant<br />

Analysis. 2, 197-224 (1955).<br />

26. C.S. Jun, M.J. Yoo, W.Y. Lee, K.C. Kwak, M.S. Bae, W.T. Hwang, D. H. SON, K.Y. Chai, Ester derivatives from<br />

tannase-treated prunioside A and their anti-inflammatory activities. Bull Korean Chem. Soc. 28, 73-76 (2007).<br />

27. B. Kar, R. Banerjee, B.C. Bhattacharya, Microbial production <strong>of</strong> gallic acid <strong>by</strong> modified solid state<br />

fermentation., J Ind Microbiol Biotechnol. 23,173-7. (1999).<br />

28. B. Kar, R. Banerjee, BC. Bhattacharyya, Effect <strong>of</strong> additives on the behavioural properties <strong>of</strong> tannin acyl<br />

hydrolase. Process Biochem. 38,1285-93 (2003).<br />

29. J. Kitajima, K. Kimizuka, Constituents <strong>of</strong> Ficus pumila leaves. Chem. Pharm. Bull. Tokyo, 46(10), 1647-<br />

1649 (1998).<br />

30. R.P. Learmonth, E. Gratton, Assessment <strong>of</strong> membrane fluidity in individual yeast cells <strong>by</strong> Laurdan<br />

Generalised polarization and multi-photon scanning fluorescence microscopy, In: Fluorescence<br />

Spectroscopy, Imaging and probes- New tools in Chemical, Physical and life science, Springer Series on<br />

Fluorescence: Methods and Applications, Springer, Heidelberg, 2, 241-252. (2002).<br />

31. P.K. Lekha, B.K. Lonsane, Comparative titers, location and properties <strong>of</strong> tannin acyl hydrolase produced <strong>by</strong><br />

<strong>Aspergillus</strong> <strong>niger</strong> PKL 104 in solid state, liquid surface and submerged fermentation. Process Biochem. 29,<br />

497-503. (1994).<br />

32. P.K. LEKHA, B.K. LONSANE, <strong>Production</strong> and application <strong>of</strong> tannin acyl hydrolase. State <strong>of</strong> the art. Adv.<br />

Appl. Microbiol. 44, 215-260 (1997).<br />

33. K. LEXANDER, E. CARLSSON, V. SCHALEN, A. SINONSSON, T. LUNDBORG, Quantities and<br />

qulaities <strong>of</strong> leaf protein concentrates from wild species and crop species grown under controlled conditions.<br />

Ann. App. Biol. 66(2), 193-216 (1970).<br />

34. N. LOKESWARI, <strong>Production</strong> <strong>of</strong> tannase through submerged fermentation <strong>of</strong> tannin-containing cashew husk<br />

<strong>by</strong> <strong>Aspergillus</strong> oryzae. Rasayan J. Chem. 3(1), 32-37 (2010).<br />

35. N. LOKESWARI, K. JAYA-RAJU, S. POLA, V. BOBBARALA, Tannin acyl hydrolase from<br />

Trichoderma viride. Int. J. Chemical and Analytical Science. 1(5), 106-109 (2010).<br />

36. B. K. LONSANE, N.P. GHILDYAL, S. BUDIATMAN, S.V. RAMAKRISHNA, Engineering aspects <strong>of</strong><br />

solid-state fermentation. Enzyme Microbiol. Technol. 7, 258-265 (1985).<br />

37. M.J. LU, C. CHEN, Enzymatic modification <strong>by</strong> tannase increases the antioxidant activity <strong>of</strong> green tea. Food<br />

Res. Int. 41, 130-137 (2008).<br />

38. M. MCDONALD, I. MILA, A. SCALBERT, Precipitation <strong>of</strong> metal ions <strong>by</strong> plant polyphenols: optimal<br />

conditions and origin <strong>of</strong> precipitation. J. Agric. Food Chem. 44, 599-606 (1996).<br />

39. P.K. MOHAPATRA, K.C. MONDAL, B.K. PATI, <strong>Production</strong> <strong>of</strong> tannase through submerged fermentation<br />

<strong>of</strong> tannin-containing plant extracts <strong>by</strong> Bacillus lichiniformis KBR6. Polish J. Microbiol. 55(4), 297-<br />

301(2006).<br />

40. P.K.D. MOHAPATRA, K.C. MONDAL, B.R. PATI, <strong>Production</strong> <strong>of</strong> tannase <strong>by</strong> the immobilized cells <strong>of</strong><br />

Bacillus licheniformis KBR6 in Ca-alginate beads. J. Appl. Microbiol. 102(6), 1462-1467 (2007).<br />

41. K.C. MONDAL, D. BANERJEE, R. BANERJEE, B.R. Pati, <strong>Production</strong> and characterization <strong>of</strong> tannase<br />

from Bacillus cer<strong>eu</strong>s KBR9. J. Gen. Appl. Microbiol., 47, pp. 263 – 267 (2001).<br />

42. O.M. NUERO, F. REYES, Enzymes for animal feeding from Penicillium chrysogenum mycelial wastes<br />

from penicillin manufacture. Lett. Appl. Microbiol. 34(6), 413-416 (2002).<br />

43. A. PANDEY, Solid state fermentation: An overview. In: Solid-state fermentation, A. Pandey (Ed.), Wiley<br />

Eastern Ltd., New Delhi, India, PP, 3-10(1994).<br />

44. A. PANDEY, P. SELVAKUMAR, C.R. SOCCOL, P. NIGAM, Solid-state fermentation for the production<br />

<strong>of</strong> industrial enzymes. Curr. Sci. 77: 146-162 (1999).<br />

45. R. PARANTHAMAN, R.R. VIDYALAKSHMI, S. MURUGESH, K. SINGARAVADIV, Optimization <strong>of</strong><br />

fermentation conditions for production <strong>of</strong> tannase enzyme <strong>by</strong> <strong>Aspergillus</strong> oryzae using sugarcane bagasse<br />

and rice straw. Global J. Biotechnol. Biochemist., 3, 105-110 (2008).<br />

46. R. PARANTHAMAN, R. VIDYALAKSHMI, S. MURUGESH, K. SINGARAVADIVE, Effects <strong>of</strong> fungal<br />

co-culture for the biosynthesis <strong>of</strong> tannase and gallic acid from grape wastes under solid state fermentation.<br />

Glob. J Biotechnol. Biochem. 4(1), 29-36 (2009).<br />

7456 Romanian Biotechnological Letters, Vol. 17, No. 4, 2012


<strong>Economic</strong> <strong>Production</strong> <strong>of</strong> <strong>Tannase</strong> <strong>by</strong> <strong>Aspergillus</strong> <strong>niger</strong> van Tiegh<br />

Adopting Different Fermentation Protocols and Possible Applications<br />

47. G.C. PAUL, C.A. KENT, C.R. THOMAS, Hyphal vaculoation and fragmentation in Penicillium<br />

chrysogenum. Biotechnol. Bioeng. 44 655-660 (1994).<br />

48. N.W. PIRIE, Proteins in modern methods <strong>of</strong> plant analysis. FIZCL. Biokhim. Kul't Rast., 8(6) 619-625. [C.<br />

F. Chemical Abstract., 86(9), 52761 (1955).<br />

49. J.S. PUROHIT, J.R. DUTTA, R.K. NANDA, R. BANERJEE, Strain improvement for tannase production<br />

from co-culture <strong>of</strong> <strong>Aspergillus</strong> foetidus and Rhizopus oryzae. Biores Technol; 97,795-801 (2006).<br />

50. G.S. RAJAKUMAR, S.C. NANDY, Isolation, purification, and some properties <strong>of</strong> Penicillium chrysogenum<br />

tannase. Appl. Environ. Microbiol. 46, 525-527 (1983).<br />

51. S.V. RAMAKRISHNA, R.S. PRAKASHAM, Microbial fermentatioins with immobilized cells. Curr. Sci.<br />

77, 87-100 (1999).<br />

52. J.D. REED, Nutritional toxicology <strong>of</strong> tannins and related polyphenols in forage legumes. J. Animal Sci.<br />

73(5), 1516-28 (1995).<br />

53. S. ROUT, R. BANERJEE, <strong>Production</strong> <strong>of</strong> <strong>Tannase</strong> under mSSF and its application in fruit juice debittering.<br />

Ind. J. Biotechnol. 5, 346-350 (2006).<br />

54. A. SABU, A. PANDEY, M. JAAFAR-DAUD, G. SZAKACS, Tamarind seed powder and palm kernel<br />

cake: two novel agro residues for the production <strong>of</strong> tannase under solid state fermentation <strong>by</strong> <strong>Aspergillus</strong><br />

<strong>niger</strong> ATCC 16620. Bioresource Technology. 96, 1223–1228 (2005).<br />

55. S.H. SCHANDERI, Methods in Food Analysis. Academic Press. New York. P, 709 (1970).<br />

56. M. SELWAL, A. YADAV, K. SELWAL, N.K. AGGARWAL, K. GUPTA, S.K. GAUTAM, <strong>Tannase</strong><br />

production <strong>by</strong> Penicillium atramentosum KM under SSF and its applications in wine clarification and tea<br />

cream solubilization. Braz. J. Microbiol. 42, 374-387 (2011).<br />

57. M. SETH, S. CHAND, Biosynthesis <strong>of</strong> <strong>Tannase</strong> and hydrolysis <strong>of</strong> tannins to gallic acid <strong>by</strong> <strong>Aspergillus</strong><br />

awamori- optimization <strong>of</strong> process parameters. Proc. Biochem. 36, 39-44 (2000).<br />

58. S. SHARMA, L. AGARWAL, R.K. SAXENA, Statistical optimization for tannase production from<br />

<strong>Aspergillus</strong> <strong>niger</strong> under submerged fermentation. Indian J. Microbiol. 47, pp. 132 – 138 (2007).<br />

59. A. SRIVASTAVA, R. KAR, Characterization and application <strong>of</strong> tannase produced <strong>by</strong> <strong>Aspergillus</strong> <strong>niger</strong><br />

ITCC 6514.07 on pomegranate rind. Braz. J. Microbiol. 40, 782-789 (2009)<br />

60. K. STORMO, R. CRAWFORD, Preparation <strong>of</strong> encapsulated microbial cells for environmental applications.<br />

App. Environ. Microbiol. 58 (2), 727-730 (1992).<br />

61. D.M. STUART, D.A. MITCHELL, J.D. JOHNS, LITSTER, Solid-state fermentation in rotating drum<br />

bioreactors: operating variables affect performance through their effects on transport phenomena.<br />

Biotechnol. Bioeng. 63, 383-391 (1999).<br />

62. B. TREVINO-CUETO, M. LUIS, J.C. CONTRERAS-ESQUIVEL, R. RODRIGUEZ, A. AGUILERA,<br />

C.N. AGUILAR, Gallic acid and tannase accumulation during fungal solid state culture <strong>of</strong> a tannin-rich<br />

desert plant (Larrea tridentata Cov.). Biores. Technol. 98, 721-724 (2007).<br />

63. R. TUNGA, R. BANERJEE, B.C. BHATTACHARYYA, Optimization <strong>of</strong> n variable biological experiments<br />

<strong>by</strong> evolutionary operation-factorial design technique. J. Biosci. Bioeng. 87(2), 125-131. (1999).<br />

64. G. URBANO, M. LOPEZ-JURADO, J.M. PORRES, S. FREJNAGEL, E. GOMEZ-VILLALVA, J. FRIAS,<br />

C. VIDALVALVERDE, P.ARANDA, Effect <strong>of</strong> treatment with α-galactosidase, <strong>Tannase</strong> or a cell-walldegrading<br />

enzyme complex on the nutritive utilization <strong>of</strong> protein and carbohydrates from pea (Pisum sativum<br />

L.) flour. J. Sci. Food Agric. 87, 1356-1363. (2007).<br />

65. J. VAN DE LAGEMAAT, D.L. PYLE, Solid state fermentation and bioremediation: development <strong>of</strong> a<br />

continuous process for the production <strong>of</strong> fungal tannase. Chem. Engin. J. 84, 115-123. (2001).<br />

66. G. WALKER, R. DE NICOLA, S. ANTHONY, R. Learmonth, Yeast-metal interactions: impact on brewing<br />

and distilling Asia Pacific Section. 19-24 March, Hobart, Tasmania. (2006)<br />

67. H.H. WANG, A review: Development and/or reclamation <strong>of</strong> bioresources with solid state fermentation.<br />

Proc. Natl. Sci. Counc. Roc (B). 23(2), 45-61. (1999).<br />

68. X. WANG, Z GAI, B. YU, J. FENG, C. XU, Y. YUAN, Z. LIN, P. XU, Degradation <strong>of</strong> carbazole <strong>by</strong><br />

microbial cells immobilized in magnetic gellan gum gel beads. Appl. Environ. Microbiol. 73(20), 6421-6428<br />

(2007).<br />

69. H.H. WEETAL, Enzymatic gallic acid esterification. Biotechnol. Bioeng. 27, 124-127 (1985).<br />

70. E.D. WEINBERG, Roles <strong>of</strong> metallic ions in host-parasite interactions. Bacteriol. Reviews. 30(1), 136-151<br />

(1966).<br />

71. Y. YALCINKAYA, M.Y. ARICA, L. SOYSAL, A. DENIZLI, O. GENC, S. BEKTAS, Cadmium and<br />

mercury uptake <strong>by</strong> immobilized Pl<strong>eu</strong>rotus sapidus. Turk J. Chem. 26, 441-452 (2002).<br />

Romanian Biotechnological Letters, Vol. 17, No. 4, 2012 7457

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!