Assessment of Bioplastic Producing Potential of Bacillus subtilis using Some Agricultural Residues as Carbon Source

Abstract

 This study was carried out to assess the bioplastic producing potential of Bacillus subtilis using a variety of pretreated agricultural residues. Four agricultural residues (rice husks, molasses, bagasse, and corn cobs) were subjected to acid, alkaline and oxidative pretreatments using standard procedures. Polyhydroxybutyrate (PHB) produced was extracted using chloroform precipitation and quantified spectrophotometrically. The PHB production (g/L) for acid, alkali and hydrogen peroxide pretreatments where (n = 3) were: 1.52±0.02, 1.82±0.01, and 1.70±0.01 for rice husk; 1.82±0.01, 1.52±0.02, and 1.69±0.01 for molasses; 0.87±0.06, 1.10±0.10, and 0.96±0.07 for sugarcane bagasses and 0.5±0.00, 0.77±0.06, and 0.60±0.10 for corn cob, respectively. The maximum bioplastic yield of 63.94±2.59% was obtained in alkali pretreated corn cobs, while the lowest yield of 50.33±0.76% was found in acid pretreated rice husk. Thus, the findings in this study revealed that agricultural residues could be explored for PHB production in the presence of potential microbial strains due to their abundance, high carbon content, limited inhibitory effect and cost effectiveness.