Statistical optimization and enhanced synthesis of polyhydroxyalkanoates from Ceiba pendantra oil as novel non-edible feedstock

Polyhydroxyalkanoates (PHA) are biopolymer synthesized as storage granules by microbes in the cell’s cytoplasm under excess carbon and limited nitrogen conditions. This study aims to examine the production and optimization of PHA from Ceiba pentandra oil, a non-edible feedstock, by Cupriavidus necator. Response surface methodology was used to optimize the concentrations of carbon, nitrogen, and inoculum for the production of PHA. To improve the physical, mechanical, and thermal properties of PHA, it was blended with polylactic acid (PLA) which possesses high bio-compatibility and bio-absorbability. Furthermore, batch mode cultivation of PHA in a 3-L bioreactor was performed under the optimized conditions (Ceiba pentandra oil—17.13 g/L, urea—1.34 g/L, and inoculum—53.42 mL/L), and 8.51 g/L (0.47 g PHA/g of Ceiba pentandra oil) of PHA product was obtained. The PHA was characterized by FTIR and the presence of functional groups such as C=O, OH, and CH were observed. 1H and 13C NMR spectroscopy revealed the existence of hydroxy valerate (HV) and hydroxybutyrate (HB), and maximal decomposition temperature was identified to be 217.7 °C from TGA analysis. Therefore, Ceiba pendantra oil appears to be an attractive alternate carbon source for PHA production.