Production and Characterization of Polyhydroxybutyrate (PHB) from an Agricultural By-Product Using Bacillus thuringiensis CICIM (B2031)

The widespread overuse of petroleum plastics has led to serious environmental challenges. This has necessitated the pursuit of greener alternatives that would reduce or eliminate mankind’s unsustainable and toxic dependence on the recalcitrant petroleum plastics. Polyhydroxybutyrate (PHB) is a potential substitute candidate for the production of biodegradable plastics. In this study, Bacillus thuringiensis CICIM (B2031) was utilized for the production of PHB using the agricultural by-product corn silage as a carbon source. The corn silage was pretreated with dilute sulfuric acid. The acid-pretreated corn silage hydrolysate was used at different loadings, producing a maximum biopolymer yield of 53.43% PHB. This was compared with the untreated corn silage which gave a maximum yield of 28.63% PHB, under the same conditions. The extracted PHB biopolymer was characterized using FourierTransform Infrared Spectroscopy (FT-IR), ultraviolet–visible (UV-Vis) spectroscopy, and gas chromatography-flame ionization detector (GC-FID). This study revealed that corn silage (CS) can be utilized as a renewable carbon source for PHB production.