Bacterial synthesis of poly(hydroxybutyrate- co-hydroxyvalerate) using carbohydrate-rich mahua (Madhuca sp.) flowers.

Anil Kumar, P. K. and Shamala, T. R. and Kshama, L. and Prakash, M. H. and Joshi, G. J. and Chandrashekar, A. and Latha Kumari, K. S. and Divyashree, M. S. (2007) Bacterial synthesis of poly(hydroxybutyrate- co-hydroxyvalerate) using carbohydrate-rich mahua (Madhuca sp.) flowers. Journal of applied microbiology, 103 (1). pp. 204-9. ISSN 1364-5072

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Abstract

AIMS: The objective of the present work was to utilize an unrefined natural substrate namely mahua (Madhuca sp.) flowers, as a carbon source for the production of bacterial polyhydroxyalkanoate (PHA) copolymer by Bacillus sp-256. METHODS AND RESULTS: In the present work, three bacterial strains were tested for PHA production on mahua flower extract (to impart 20 g l(-1) sugar) amongst which, Bacillus sp-256 produced higher concentration of PHA in its biomass (51%) compared with Rhizobium meliloti (31%) or Sphingomonas sp (22%). Biosynthesis of poly(hydroxybutyrate-co-hydroxyvalerate) - P(HB-co-HV)--of 90 : 10 mol% by Bacillus sp-256 was observed by gas chromatographic analysis of the polymer. Major component of the flower is sugars (57% on dry weight basis) and additionally it also contains proteins, vitamins, organic acids and essential oils. The bacterium utilized malic acid present in the substrate as a co-carbon source for the copolymer production. The flowers could be used in the form of aqueous extract or as whole flowers. PHA content of biomass (%) and yield (g l(-1)) in a 3.0-l stirred tank fermentor after 30 h of fermentation under constant pH (7) and dissolved oxygen content (40%) were 54% and 2.7 g l(-1), respectively. Corresponding yields for control fermentation with sucrose as carbon source were 52% and 2.5 g l(-1). The polymer was characterized by proton NMR. CONCLUSIONS: Utilization of mahua flowers, a natural substrate for bacterial fermentation aimed at PHA production, had additional advantage, as the sugars and organic acids present in the flowers were metabolized by Bacillus sp-256 to synthesize P(HB-co-HV) copolymer. SIGNIFICANCE AND IMPACT OF THE STUDY: Literature reports on utilization of suitable cheaper natural substrate for PHA copolymer production is scanty. Mahua flowers used in the present experiment is a cheaper carbon substrate compared with several commercial substrates and it is rich in main carbon as well as co-carbon sources that can be utilized by bacteria for PHA copolymer production.

Item Type:	Article
Uncontrolled Keywords:	Bacillus sp, mahua flowers, natural substrate, PHA accumulation, poly(hydroxybutyrateco- hydroxyvalerate
Subjects:	500 Natural Sciences and Mathematics > 10 Plants 500 Natural Sciences and Mathematics > 07 Life Sciences > 04 Microbiology > 02 Bacteriology
Divisions:	Food Microbiology Plant Cell Biotechnology
Depositing User:	Food Sci. & Technol. Information Services
Date Deposited:	09 Aug 2008 04:56
Last Modified:	07 May 2012 04:30
URI:	http://ir.cftri.res.in/id/eprint/1854

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