EMCB-ENVIS Node ENVIRONMENTAL BIOTECHNOLOGY

EMCB-ENVIS Centre
About 0.7 g cell dry weight were formed from 1 g hydrocarbon. The experiments demonstrate
the feasibility and efficiency of extreme thermophilic PAH and alkane biodegradation.
Helia Radianingtyas, Phillip C. Wright. (Biochemical Engineering and Environmental
Technologies Group, Department of Chemical and Process Engineering, Heriot-Watt
University, Riccarton, Edinburgh EH14 4AS, UK. Biological and Environmental Systems
Group, Department of Chemical and Process Engineering, University of Sheffield, Mappin
Street, Sheffield S1 3JD, UK). 2-Propanol degradation by Sulfolobus solfataricus.
Biotechnology Letters, 25(7) (2003), 579-583.
Sulfolobus solfataricus used 2-propanol and 2-propanone (acetone) when grown in static cultures
at 78 °C with or without glucose at 10 g l-1. The presence of 3.92 g 2-propanol l-1 in both cases
inhibited growth. However, acetone accumulation following 2-propanol depletion suggested that
2-propanol was co-metabolized via the acetone metabolic pathway. Glucose at 10 g l-1 increased
2-propanol and acetone utilization from 0.93 g l-1 to 1.77 g l-1 and from 0.11 g l-1 to 1.62 g l-1,
respectively. Without glucose, immobilized S. solfataricus cells increased the 2-propanol
removal rate to 0.035 g l-1 h-1, compared to 0.0012 g l-1 h-1 by its suspended counterpart. The
results suggest the establishment of an immobilized reactor configuration is preferential for the
treatment of high temperature solvent waste streams by this acidothermophilic Crenarchaeon.
Hojae Shima, EungBai Shina, Shang-Tian Yangb. (Department of Civil and Environmental
Engineering, Hanyang University, 1271 Sa-1-Dong, Ansan, Kyungkido 425-791, South
Korea. Department of Chemical Engineering, The Ohio State University, 140 West 19th
Avenue, Columbus, OH 43210, USA). A continuous fibrous-bed bioreactor for BTEX
biodegradation by a co-culture of Pseudomonas putida and Pseudomonas
fluorescens. Advances in Environmental Research,7(4)(2003),889-900.
A co-culture of Pseudomonas putida and P. fluorescens immobilized in a fibrous-bed bioreactor
was used to degrade benzene, toluene, ethylbenzene and xylenes (collectively known as BTEX),
present as sole carbon sources in contaminated water. The kinetics of BTEX biodegradation in
the fibrous-bed bioreactor operated under the liquid-continuous condition was studied.
Biodegradation rates of BTEX increased with increasing BTEX concentration and reactor
loading rate. For benzene, the maximum biodegradation rate was 38 mg/l/h at a loading rate of
265 mg/l/h. For toluene, the rate was 45 mg/l/h at a 100 mg/l/h loading rate. Aeration was not
used in the process and the addition of hydrogen peroxide (H2O2) as an additional oxygen
source improved benzene and toluene biodegradation for the high strength synthetic wastewater
feeds. When benzene, toluene, ethylbenzene and para-xylene were present as a mixture in the
feed, they were concurrently and completely biodegraded under hypoxic conditions (no addition
of air or H2O2). The total BTEX biodegradation rate was as high as 600 mg/l/h at the highest
BTEX loading rate, 1000 mg/l/h, studied. Individual BTEX compounds were efficiently and
concurrently degraded at a retention time of less than 15 h. Immobilized cells adapted in the
bioreactor showed no preferential degradation of BTEX present as mixtures. The bioreactor also
had a stable long-term performance, maintaining its ability for efficient BTEX degradation
without requiring additional nutrients (e.g. glucose) for more than 1 year. The good performance
of the fibrous-bed bioreactor was attributed to the high cell density and unique cell
immobilization process provided by the fibrous matrix, which allowed use of the reactor for
continued regeneration, adaptation and selection of efficient BTEX degraders in the bioreactor
environment.
Hong-Gyu Song. (Division of Biological Sciences, Kangwon National University Hyoja-dong
192-1, Chuncheon 200-701, South Korea). Degradation of humus-bound metabolites
generated from toluene and o-xylene in soil. International Biodeterioration &
Biodegradation, 51(2) (2003), 129-132.
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