full issue - Association of Biotechnology and Pharmacy

More documents

Recommendations

Info

Current Trends in Biotechnology and PharmacyVol. 5 (1) 982-992 January 2011. ISSN 0973-8916 (Print), 2230-7303 (Online)98921). The higher β-glucosidase activity could haveresulted in releasing higher amount of total sugarsin the GS enzymatic hydrolysate. Recently, Dienet al. (5) also observed a key role of β-glucosidasein monosaccharide yields after enzymatichydrolysis of hot water treated corn fiber.Enzymatic hydrolysisEnzymatic hydrolysis of NaOH pretreatedGS was carried out using concentrated enzymaticsolution of (cellulase, 30 FPU g -1 ; β-glucosidase,55 U g -1 ; xylanase, 150 U g -1 of the dry substrate)Aspergillus sp. RCAL-5. Time course ofenzymatic saccharification of GS is shown inFigure 8. Saccharification of NaOH pretreatedGS shell yielded maximum sugars (0.64 g g -1 ) withthe hydrolysis efficiency of 63.12%. Thesefindings can be fairly compared with the reportsof Sharma et al. (22) who observed 59.8 %saccharification efficiency from sunflower hullsafter pretreatment with sodium hydroxide 0.5%(w/v). Saha and his coworkers (11) also showedan enzymatic hydrolytic efficiency of 64 % totalcarbohydrates (485 mg g -1 ) from wheat strawusing the commercial cellulases. The hydrolyticefficiency of lignocellulosic substrates alsodepends upon the substrate used. Recently,Chandel et al. (10) reported 77.85±0.45%hydrolytic efficiency from a weed material,Saccharum spontaneum using the cellulasesderived from A. oryzae MTCC 1846.Ethanol fermentationA typical fermentation profile of GSenzymatic hydrolysate using P. stipitis NCIM3498 utilizing 49 g l -1 total sugars is shown in Figure9. A regular increase in ethanol production wasobserved till 84 h of fermentation and declinedthereafter. About 86.5 % of the available sugarswere utilized within 84 h giving an ethanol yieldof 0.46 g g -1 sugar utilized. The fermentationparameters viz. ethanol yield, biomass yield,ethanol productivity etc. are summarized inTable 3.Table 3. Fermentation parameters of the P.stipitis NCIM3498 when grown in the Groundnutshell enzymatic hydrolysateParameters studiedValuesInitial sugar concentration (gs l-1 ) 49Sugar utilization (%) 86.50Ethanol (g pl -1 ) 19.4-1Ethanol yield (g pg s) 0.46Biomass (g xl -1 ) 3.4-1Biomass yield (g xg s) 0.08Volumetric ethanol 0.23productivity (g pl -1 h -1 )Biomass productivity (gx l-1 h -1 ) 0.04Sugar uptake rate (gs l-1 h -1 ) 0.50-1Specific ethanol productivity (g pg xh -1 ) 0.06Total incubation time- 84 h. The data presentedare averages of three independent analysis.Among the xylose fermenting yeasts, P.stiptis has been promising in utilizing maximumfermentable sugars present in lignocellulosehydrolysates which in turn reflects in the higherethanol production with a greater yield. In general,the fermentation performance of P. stipitis islower than the conventionally used ethanologen,Saccharomyces cerevisiae or Zymomonasmobilis. But looking the ability of P. stipitis forutilization of almost all sugars present in thelignocellulose hydrolysates, this microorganism isconsidered ideal in biorefineries. S. cerevisiae orZ. mobilis utilize C 6sugars or sucrose highlyefficiently but their inability to utilize C 5sugarsmake them inappropriate candidates forbiorefineries (3, 4). Our results were similaraccording to the earlier reports summarized inTable 4.Chandra Sekhar et al
Current Trends in Biotechnology and PharmacyVol. 5 (1) 982-992 January 2011. ISSN 0973-8916 (Print), 2230-7303 (Online)990Table 4. Bioethanol Production from various agro residues by different strains of P. stipitisAgro Sugar Strain Ethanol Referenceresidues concentra- production(g/L)tion (g/L)Hazelnut shell 50 Pichia stipitis 16.79 23Wheat straw 46 Pichia stipitis. NRRL Y-7124. 12.9 24Saccharum 53.9 Pichia stipitis NCIM3498. 21.82 25spontaneumProsopis 18.24 Pichia stipitis NCIM3498 7.13 26julifloraDeoiled rice bran 33.55 Pichia stipitis NCIM3499 12.47 8Lantana camara 19.4 Pichia stipitis NCIM3498 5.16 27(red sage)Yellow poplar 89.2 Pichia stipitis KCCM 12009 28.7 28Sugar maple 59.9 Pichia stipitis. NRRL Y-7124 14.3 29ConclusionsGS after pretreatment with alkali yielded63.12 % hydrolytic efficiency using the enzymesfrom a novel isolate, Aspergillus sp. RCAL-5. Itwas optimized for cellulase production undershake flask conditions.The obtained GS enzymatic hydrolysatewas fermented with P. stipitis NCIM3498 forethanol production at 10 l fermenter level. Amaximum of 19.4 g l -1 ethanol was produced withthe yield (0.46 g g -1 sugar utilized) and productivity(0.23 g l -1 h -1 ). This study proved GS as a potential,renewable and low cost biomass for ethanolproduction on a commercial scale.AcknowledgementsAuthors are highly thankful of Mr. G.Balanarsimha Reddy for providing the Groundnutshell and technical help for this study.References1. Chandel, A.K., Singh, O.V., Chandrasekhar,G., Rao, L.V. and Narasu, M.L. (2010).Key-drivers influencing the commercializationof ethanol based biorefineries. Journalof Commercial Biotechnology, 16:239-257.2. Herrera, S. (2004). Industrial biotechnology-a chance at redemption. Nature Biotechnology,22:671-675.3. Wyman, C.E. (2007). What is (and is not)vital to advancing cellulosic ethanol. Trendsin Biotechnology, 25: 153-157.4. Lynd, L.R., Laser, M.S., Bransby, D., Dale,B.E., Davison, B., Hamilton, R., Himmel,M., Keller, M., McMillan, J.D., Sheehan, J.and Wyman, C.E. (2008). How biotech cantransform biofuels. Nature Biotechnology,26:169-172.Fermentation of Enzymatically Saccharified Groundnut
Page 3 and 4: ISSN 0973-8916Current Trends inBiot
Page 5 and 6: Current Trends in Biotechnology and
Page 23: Current Trends in Biotechnology and
Page 75 and 76:
Current Trends in Biotechnology and
Page 77 and 78:
Page 79 and 80:
Page 81 and 82:
Page 83 and 84:
Page 85 and 86:
Page 87 and 88:
Page 89 and 90:
Page 91 and 92:
Page 93 and 94:
Page 95 and 96:
Page 97 and 98:
Page 99 and 100:
Page 101 and 102:
Page 103 and 104:
Page 105 and 106:
Page 107 and 108:
Page 109 and 110:
Page 111 and 112:
Page 113 and 114:
Page 115 and 116:
Page 117 and 118:
Page 119 and 120:
Page 121 and 122:
Page 123:
show all

full issue - Association of Biotechnology and Pharmacy

Create successful ePaper yourself

Delete template?

Save as template?