Production and characterization of polyhydroxybutyrate (PHB) BY Burkholderia cepacia BPT1213 using waste glycerol as carbon source

Abstract

This study focused on the utilization of waste glycerol, a by-product of the biodiesel industry, used as a carbon source to grow Burkholderia cepacia BPT1213 for the production of PHB. B. cepacia BPT1213 was cultivated in minimal salt media (MSM) supplemented with waste glycerol at concentrations ranging from 2% to 9% (v/v). A gradual decrease was depicted by the cell dry weight (CDW) and PHB content with increasing waste glycerol content. B. cepacia BPT1213 is able to synthesize and accumulate up to 2.41 g/L and 66.4% dry biomass and PHB yield respectively when supplemented with 2% (v/v) waste glycerol. This resulted in a total PHB concentration of 1.6 g/L. The characterization of extracted PHB was carried out by Nuclear magnetic resonance (NMR) and Fourier-transform infrared spectroscopy (FTIR) for structural composition evaluation. Both analyses showed expected signals for PHB as reported in other studies which depicted the methyl, methylene and methine groups for NMR analyses, and certain functional groups which were the hydroxyl group, carbonyl stretch and ester group for FTIR. This study demonstrated the effects of waste glycerol concentration on the end properties of PHB, which is an important aspect for its applications.