Research Article
Adrian D Allen, Folahan O A
Abstract
Since the oil crisis of the 1970s much attempt has been made, albeit with varying degrees of success, to source the ideal substrate and bacteria for the production of PHA. The non-edible, naturally epoxidized seed oil from Vernonia galamensis and mixed cultures consisting of Alcaligenes latus (ATCC 29712), Cupriavidus necator (ATCC 17699), Escherichia coli (DH5α) and Pseudomonas oleovorans (ATCC 29347), were evaluated for PHA production under batch and fed-batch fermentations. PHA production, optimized by the mixed culture of E. coli and C. necator, was 0.4-19% (%wt/wt, cdw) for batch and fed-batch fermentations. Analyses of PHA by Matrix Assisted Laser Desorption Ionization- Time of Flight Mass Spectrometry (MALDI-TOF MS) and Gas Chromatography Mass Spectrometry (GC/MS) identified the 3-hydroxybutyrate (3HB) monomeric unit. The PHA ester bond stretching vibration (C=O), was confirmed at absorption 1740.66 cm-1, using Fourier Transform Infrared Spectroscopy (FTIR). Gel Permeation Chromatography (GPC) indicated peak molecular weights between 3.8×103-1.12×106 Da with melting points (Tm), 60-90°C. The data further illustrates that inedible oils could be the ideal carbon source for the production of PHA.