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Isolation and acclimation of a microbial consortium for improved aerobic degradation of alpha-hexachlorocyclohexane.

Manonmani, H. K. and Chandrashekaraiah, D. H. and Sreedhar Reddy, N. and Elcey, C. D. and Kunhi, A. A. M. (2000) Isolation and acclimation of a microbial consortium for improved aerobic degradation of alpha-hexachlorocyclohexane. Journal of agricultural and food chemistry, 48 (9). pp. 4341-51. ISSN 0021-8561

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A microbial consortium that can utilize alpha-hexachlorocyclohexane (alpha-HCH) as a sole source of carbon and energy was isolated from soil and sewage through a novel technique involving an initial enrichment in a glass column reactor followed by a shake flask enrichment. This consortium took 14 days to completely mineralize 5 and 10 microg mL(-)(1) alpha-HCH in mineral salts medium in shake flasks. The degradative ability of this consortium improved very markedly on acclimation by successive and repeated passages through media containing increasing concentrations of alpha-HCH. The acclimated consortium could degrade 100 microg mL(-)(1) of alpha-HCH within 72 h at a degradation rate of 58 microg mL(-)(1) day(-)(1) with concomitant release of stoichiometric amounts of chloride. Accumulation of any intermediary metabolites was not detected in the culture broth as tested by TLC and GC, implying complete mineralization of the substrate. The acclimated consortium contained eight bacterial strains and a fungus. The individual strains and the different permutations and combinations of them, however, were able to utilize only 10 microg mL(-)(1) of alpha-HCH. Mesophilic temperatures (20-30 degrees C) and near-neutral pH (6.0-8.0) were most favorable for alpha-HCH degradation. Among the auxiliary carbon sources tested, ethanol, benzoate, and glucose (at higher concentrations) retarded the degradation of alpha-HCH, whereas the addition of cellulose, sawdust, and low concentrations of glucose (<200 microg mL(-)(1)) and acetone enhanced the rate of degradation.

Item Type: Article
Uncontrolled Keywords: R-Hexachlorocyclohexane; microbial consortium; acclimation; biodegradation; cosubstrate
Subjects: 500 Natural Sciences and Mathematics > 05 Earth Sciences > 03 Environmental Sciences
Divisions: Food Microbiology
Depositing User: Food Sci. & Technol. Information Services
Date Deposited: 05 Jan 2009 08:59
Last Modified: 09 May 2012 04:08
URI: http://ir.cftri.com/id/eprint/2149

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