Bioconversion of Calophyllum inophyllum oilcake for intensification of rhamnolipid and polyhydroxyalkanoates co-production by Enterobacter aerogenes

The biologically derived products are highly valued due to their biodegradability, low toxicity, and renewability. However, most production processes are exorbitant due to high raw material cost and the downstream processing required for product recovery and purification. Therefore, the present study utilized the low-cost lignocellulosic biomass, Calophyllum inophyllum oilcake for the simultaneous production of PHA and rhamnolipid by a facultative anaerobe Enterobacter aerogenes. Both the products are produced during the stationary phase and constitute beta-hydroxyalkanoic acids, which makes it feasible for the co-production through a single fermentation process. From the batch fermentation studies, it was revealed that the under optimum condition rhamnolipid and PHA yield are 5.81 g/L and 4.2 g/L: 5%(v/v) of inoculum size, pH of 6.5, C:N ratio of 5:1 and urea are found to be the best nitrogen source for the fermentation process. Characterization studies for extracted PHA and RL was done using- FTIR, NMR and TGA analysis.