Synthesis and characterization of poly-β-hydroxybutyrate from Bacillus thuringiensis R1

A poly-β-hydroxybutyrate (PHB) accumulating, Gram positive Bacillus thuringiensis R1 was isolated from the soil samples. The growth of the organism and PHB accumulation in the presence of different carbon sources was studied. While maximum dry cell mass accumulation (3.90 to 4.11g/L) resulted in the presence of glycerol (1% v/v), least biomass formation (1.28g/L) was in the presence of 1%(v/v) lactic acid. Glycerol also supported maximum accumulation of PHB (34.18 to 34.23%) on cell dry mass basis. PHB accumulation in the presence of table sugar (sucrose) and molasses was 28.23 % and 23.06%, respectively. No PHB accumulation was observed in the presence of acetic acid or ethanol. B. thuringiensis R1 cells grown to log phase in the basal medium in the absence of a additional carbon source and then reinoculated into the same medium supplemented with 1% (v/v) glycerol or 1% (w/v) table sugar accumulated 64.10% and 31.36% PHB of the dry cell mass, respectively. The recovered polymer was characterized by NMR, FTIR, GPC, DSC and TGA.