Biodegradable Polymeric Substances Produced by a Marine Bacterium from a Surplus Stream of the Biodiesel Industry

Abstract

Crude glycerol is generated as a by-product during transesterification process and during hydrolysis of fat in the soap-manufacturing process, and poses a problem for waste management. In the present approach, an efficient process was designed for simultaneous production of 0.2 g/L extracellular ε-polylysine and 64.6% (w/w) intracellular polyhydroxyalkanoate (PHA) in the same fermentation broth (1 L shake flask) utilizing <i>Jatropha</i> biodiesel waste residues as carbon rich source by marine bacterial strain (<i>Bacillus licheniformis</i> PL26), isolated from west coast of India. The synthesized ε-polylysine and polyhydroxyalkanoate PHA by <i>Bacillus licheniformis</i> PL26 was characterized by thermogravimetric analysis (TGA), differential scanning colorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), and ¹H Nuclear magnetic resonance spectroscopy (NMR). The PHA produced by <i>Bacillus licheniformis</i> was found to be poly-3-hydroxybutyrate-co-3-hydroxyvalerate (P3HB-co-3HV). The developed process needs to be statistically optimized further for gaining still better yield of both the products in an efficient manner.