Document Type : Original Article
Department of Microbiology, Wilson College, Mumbai 400007, Maharashtra, India
Introduction: The last four decades have recognized the critical environmental issues pertaining to the use of non-degradable synthetic plastics. Currently, the synthesis of biodegradable polymers, like polyhydroxyalkaonoates (PHA) has been gaining considerable interest as a sustainable approach to overcome these issues. The current study was carried out with an objective to optimize the PHA production from Bacillus megaterium JHA.
Materials and Methods: Various nutritional and physico-chemical parameters were optimized using the ‘one factor at a time’ approach. The findings were analysed statistically by one-way ANNOVA and linear regression using the open-source R software.
Results: The optimum physico-chemical parameters for maximum PHA production were attained when 5% inoculum size of B. megaterium JHA was added to the JHA medium (pH 8) and incubated at 28 °C for 96 h under shaker conditions (120 rpm). The nutritional parameters were further optimized by addition of 0.6 g% K2HPO4, 0.4 g% KH2PO4, 21 g% glucose, 12.5 mM microcosmic salt, 0.04 g% KNO3, 1 mM MgSO4, and 2 ml trace elements to the JHA medium. The C:N and C:P ratio was adjusted to 70:1 and 20:1 respectively. The growth of bacteria under these optimized parameters allowed 13.71 g/L accumulation of PHA leading to a yield of 54.51%. This resulted in 66.88% increase in yield as compared to the original medium. The scale-up study using a 2 L fermenter further increased PHA accumulation by 4.39% under optimized conditions.
Conclusions: The above results clearly indicate that B. megaterium JHA is a promising isolate that can be exploited for the industrial production of PHA.