Effective utilization and management of coir industrial waste for the production of poly-β - hydroxybutyrate (PHB) using the bacterium Azotobacter beijerinickii

Coir pith, a byproduct of coconut fibers and waste material from the coir industry, is stable and not easily degradable due to its high lignin content. Coir pith takes a decade to decompose thereby posing environmental hazard and disposal problem. Pollution by plastics creates an alternative solution to reduce problems. Hence the potential use of coir industrial wastes for production of bioplastics (Poly-(-hydroxybutyrate - PHB) as an alternative to plastics was studied. Commercial production of this polymer is limited, however, due to higher cost and longer fermentation process as compared to petrochemical plastics. These concerned make it necessary to use the cheapest and readily available raw materials. Azotobacter beijerinickii used coir industrial waste as a substrate and produced PHB. Production of PHB was maximized at pH 6.5 with 3% coir hydrolysate. The amount of PHB produced by A. beijerinickii was 2.4 ± 0.2 g/L. The yield was 48.19 %. Production of PHB was confirmed by Sudan black B staining under a light microscope, acridine orange staining under a fluorescent microscope and by an infrared spectrometer. This investigation showed that coir industrial waste could be effectively used for the production of PHB