Statistical augmentation of polyhydroxybutyrate production by Isoptericola variabilis: Characterization, moulding, in vitro cytocompatibility and biodegradability evaluation.

This study aimed to explore the production of polyhydroxybutyrate (PHB), a polyhydroxyalkanoate (PHA), which has been widely considered as a potential substitute for the synthetic polymers. Among 53 actinomycete isolates, 11 of them were found to be PHB positive and the quantity of PHB from the positive isolates varied from 10.5 to 29.82 wt% on a dry cell weight basis. A strain designated as PPLAT 012, accumulated relatively higher PHB and has been identified as Isoptericola variabilis by 16S rRNA gene sequence analysis. An effort has also been made to optimize the PHB production by the hyper-producing strain using the conventional, one-factor-at-a-time, and statistical response surface methodologies and the maximum PHB production (46.18%) in DSMZ medium, amended with 12% glucose and 9% potassium nitrate with a pH of 7.0. Further, the characteristic properties such as processability, cytocompatibility and biodegradability of the extracted PHB was also demonstrated. The physical properties of the recovered PHB was further improved by blending with PLA and the resultant blends were characterized. The present investigation has demonstrated that the isolate, Isoptericola variabilis, could be utilized as a potential source for the production of PHB with desirable characteristics, suitable for biomedical applications.