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Polyhydroxyalkanoate (PHA) production from Amphibacillus sp.

Pushpa S.Murthy, M.Madhumathi

Many bacteria accumulate Polyhydroxyalkanoate (PHA) as an energy resource. The microbial thermoplastics are regarded as potentially useful polyester replacing petroleum-derived thermoplastics. Polyhydroxy butyrate (PHB) is the best-known member of the PHA series of polyesters. PHB producing strain of Amphibacillus sp was isolated from polymer industry soil and identified by comparison with keys given in Bergey’s manual of determinative bacteriology. The initial yield of PHAwas 39.90  0.5%in the production medium. Different carbon and nitrogen sources were tested for PHB production by this bacterium Maximum yield of PHA was observed with glucose (82.20  0.4 %) followed by fructose (47.09  0.51%) and mannose (47.09 0.4%), arabinose (41.42  0.5%). Sucrose, being a cheaper substrate, was used for further studies. Among the nitrogen sources beef extract and tryptone promoted PHB synthesis with 42.42  0.3 % and 41.65  0.02 % respectively. Growth conditions for production of PHAby the Amphibacillus sp were studied. The optimized conditions with 30  0.50C of temperature and pH 7.0  0.1with 3%inoculumat 250 rpmat 48 h of fermentation using sucrose as the carbon source yielded 67.03  0.5% of PHB. The PHB produced was analyzed and confirmed by FTIR and NMR.