Bio-plastic (P-3HB-co-3HV) from Bacillus circulans (MTCC 8167) and its biodegradation

Polyhydroxyalkanoates (PHAs) are naturally occurring polyesters synthesized by bacteria for carbon and energy storage and it has commercial potential as bioplastic. The bacterial species Bacillus circulans MTCC 8167, isolated from crude oil contaminated soil, can efficiently produce medium chain length polyhydroxyalkanoates (P-3HB-co-3HV) from cheap carbon sources like dextrose. The molecular mass of P-3HB-co-3HV was reported as 5.1 × 104 Da with polydispersity index of 1.21 by gel permeation chromatography. In the present investigation different bacteria and fungi species were used for testing the biodegradability of the extracted polymer. The FTIR spectra of the biodegraded PHBV film showed a decrease in the peak from 1735 cm−1 (untreated film) to 1675 cm−1, and disappearance of a peak present in the control at 2922 cm−1 indicating the breakdown of ester (>CO) or O–R group and –CH bond, respectively. From biodegradability testing, the tested microorganisms were found to have decisive contribution to the biodegradation of P-3HB-co-3HV polymer.

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► Isolation of low polydispersity index (1.21) polymer from Bacillus circulans.
► Identification (FTIR and NMR) of ‘P-3HB-co-3HV’ from B. circulans (MTCC 8167).
► Biodegradation of ‘P-3HB-co-3HV’.