Production, optimization and characterization of polyhydroxybutyrate, a biodegradable plastic by <i>Bacillus</i> spp.

<div><p>Poly-β-hydroxybutyrate (PHB) is the intracellular lipid reserve accumulated by many bacteria. The most potent terrestrial bacterium <i>Bacillus cereus</i> SE-1 showed more PHB accumulating cells (22.1 and 40% after 48 and 72 h) than that of the marine <i>Bacillus</i> sp. CS-605 (5 and 33% after 48 and 72 h). Both the isolates harbored <i>phbB</i> gene and the characteristics C=O peak was observed in the extracted PHB by Fourier transformed infrared spectroscopy analysis. Maltose was found to be the most suitable carbon source for the accumulation of PHB in <i>B. cereus</i> SE-1. The extracted PHB sample from <i>B. cereus</i> SE-1 was blended with a thermoplastic starch (TS) and an increased thermoplasticity and decreased crystallinity were observed after blending in comparison to the standard PHB. The melting temperature (<i>T</i>_m), melting enthalpy (∆Hf), and crystallinity (<i>X</i>_c) of the blended PHB sample were found to be 109.4 °C, 64.58 J/g, and 44.23%, respectively.</p>