Polyhydroxyalkanoate production from statistically optimized media using rice mill effluent as sustainable substrate...

The present study focuses on the optimization of the bioprocess for the fermentative production of polyhydroxyalkanoate (PHA) by Acinetobacter junii BP 25 using rice mill effluent as a cheap substrate, henceforth to develop an economically feasible biopolymer production process. Statistical tools like Plackett-Burman design (PBD) and Response Surface Methodology (RSM) were used to evaluate the important variables that influence the yield of PHA. Initially from PBD three factors (glycerol, KH₂PO₄ and incubation time) were taken for further optimization using Box-Behnken design where, the interaction between each of the factors were studied in detail, providing a final optimized media for the high concentration of PHA. Before the optimization process the concentration of PHA was 0.52 ± 0.05 g/l for 1.07 ± 0.32 g/l cell dry mass (CDM) after which a 5.84 fold increase in PHA concentration was observed with 3.04 g/l of PHA. Biodegradation studies of the produced PHA sheets were investigated briefly in both terrestrial and aquatic ecosystem, showing degradation within 8 weeks in soil and 4 weeks in water which was very promising, as the non-degrading property of the conventional plastic have made scientist to research on biopolymers mainly.