Phylogenetic characterization and optimization of waste-valorizing Priestia megaterium GASCKPHA2 for sustainable polyhydroxyalkanoate production.

Polyhydroxyalkanoate (PHA) is a microbial polyester naturally produced by many microbes as a starvation reservoir. However, their large-scale production is limited due to their high production cost. This study focused on the issue mentioned above by using readily available renewable materials as carbon sources for PHA production. The main aim of this study was to screen and identify a potential bacterium obtained from renewable organic materials for PHA production. The isolates were tested for their PHA-producing ability by primary and secondary screening methods, and the most efficient isolate was identified as Priestia megaterium GASCKPHA2 through phylogenetic studies. The culture conditions were optimized using one- factor-at-a time to increase PHA production using renewable, low-cost carbon substrates. The difference among the results were statistically analyzed. Among all substrates, banana peel extract was found to support high PHA production. The polymer was extracted and analyzed using SEM, FTIR and proton NMR. The characterization studies provide supporting evidence that the extracted polymer was Polyhydroxybutyrate (PHB) like PHA. The extracted polymer was fabricated into a flexible film, to demonstrate its film forming ability. Further studies are required to evaluate its material properties to evaluate its suitability for biodegradable packaging applications. This study also highlights the application of microbial biotechnology for agro-waste valorization by P. megaterium for sustainable polymer production within a circular bioeconomy framework.