Standardization of biopolymer production from seaweed associative bacteria

•This study provides experimental evidence that marine Seaweed associated bacteria are capable of producing PHA.•The waste substrates collected from industries were used as substrate.•First study to report Pseudomonas pseudoalcaligens RBL7 for the production of PHA.•Functional groups were identified using FT – IR and GC–MS.•PHA granules were confirmed through SEM analysis. Polyhydroxyalkanoate (PHA) is the biodegradable plastic, which is shown the similar properties to the synthetic plastic. Production of PHA is expensive when compared with petrochemical based plastics costs and also hazardous to ecosystem. In order to overcome these drawbacks, some cheaper commercially available carbon sources like rice bran, coconut cake, palm jaggary, etc. can be used. The present study aimed to identify the potential PHA producing bacterial strains from different seaweeds. Based on PHA production and crotonic acid assay, two bacterial strains were screened and designated as M3 and S6 which were found to be efficient PHA producers. Potential PHA producers of M3 and S6 were identified as Bacillus cereus RBL6 and Pseudomonas pseudoalcaligens RBL7 by 16S rRNA gene sequencing. The physical and nutritional parameters such as pH, temperature, incubation period, substrate, carbon and nitrogen concentration have been used for enhancing PHA production which was served as precursor. The purified PHA had been chemically characterized by FT-IR, GC–MS and viewed through SEM.