Bacterial synthesis of poly(hydroxybutyrate- co-hydroxyvalerate) using carbohydrate-rich mahua (Madhuca sp.) flowers
- 1 July 2007
- journal article
- Published by Oxford University Press (OUP) in Journal of Applied Microbiology
- Vol. 103 (1), 204-209
- https://doi.org/10.1111/j.1365-2672.2006.03221.x
Abstract
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. 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. 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. 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.Keywords
This publication has 15 references indexed in Scilit:
- Metabolic improvements and use of inexpensive carbon sources in microbial production of polyhydroxyalkanoatesJournal of Bioscience and Bioengineering, 2002
- Production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) by Ralstonia eutropha in whey and inverted sugar with propionic acid feedingProcess Biochemistry, 2002
- Effects of culture conditions on the production of polyhydroxyalkanoates by Azotobacter chroococcum H23 in media containing a high concentration of alpechı́n (wastewater from olive oil mills) as primary carbon sourceJournal of Biotechnology, 2002
- Production of PHB by a Bacillus megaterium strain using sugarcane molasses and corn steep liquor as sole carbon and nitrogen sourcesMicrobiological Research, 2001
- Economic Analysis on Production of Bacterial Polyhydroxyalkanoates from Palm Oil Mill Effluent.JOURNAL OF CHEMICAL ENGINEERING OF JAPAN, 1997
- Production of poly(3-hydroxyalkanoates) from ?, ?-alkanedioic acids and hydroxylated fatty acids by Alcaligenes sp.Biotechnology Letters, 1993
- Production of poly-?-hydroxybutyrate by Azotobacter vinelandii strain UWD during growth on molasses and other complex carbon sourcesApplied Microbiology and Biotechnology, 1989
- Pseudomonas oleovorans as a Source of Poly(β-Hydroxyalkanoates) for Potential Applications as Biodegradable PolyestersApplied and Environmental Microbiology, 1988
- Use of Dinitrosalicylic Acid Reagent for Determination of Reducing SugarAnalytical Chemistry, 1959
- The Isolation and Estimation of the Poly- -hydroxy-butyrate Inclusions of Bacillus SpeciesJournal of General Microbiology, 1958