Halotolerant bacterial strain isolated from the Calicut coast, Kerala, India, was screened for its potential ability to synthesize polyhydroxyalkanoates (PHA) using Sudan black B and Nile blue staining. The quantitative analysis for PHA production was done in modified M9 media and a PHA yield of about 1.52 g/L was observed with the most potential isolate SG1. Further, the biochemical and molecular characterization of the PHA-producing halotolerant bacteria was done using standard biochemical tests and 16 s ribosomal RNA sequencing respectively and the isolate was identified to be Bacillus subtilis SG1. Further, the PHA recovery was done using solvent extraction method employing acetone and diethyl ether followed by precipitation using chloroform with a maximum PHA yield of 1.52 g/L. Further, the material properties of the extracted polymer were studied using Fourier transform infrared, X-ray diffraction, nuclear magnetic resonance, thermo gravimetric analysis, and differential scanning calorimetry analysis. Further investigations are necessary to optimize PHA production and to carry out its application study in various fields.
Key words: Polyhydroxyalkanoates, Bacillus subtilis, Halotolerance, Bacterial biopolymer
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