Construction of recombinant Escherichia coli strains for polyhydroxybutyrate production using soy waste as nutrient

Construction and comparison of recombinant Escherichia coli strains harbori ng the polyhydroxybutyrate (PHB) operon from Ralstonia eutropha using vecto rs possessing different promoters, as well as the production of PHB from so y waste by the recombinant strain, are reported. The lac promotor was the m ost efficient on expression of the phb operon among the three promoters stu died: i.e., lac promotor, T7 promotor and the normal sigma(70) promotor. Th e pKS/PHB was the most efficient plasmid for phb operon expression among th e three plasmids used: i.e., pKS(-), pAED4, and pJM9131. It was observed th at isopropyl-beta-D-thiogalactopyranoside was not required for the inductio n of the expression of phb operon. The cell dry wt and polyhydroxyalkanoate content by E. coli XL-1 Blue (pKS/PHB) were 3.025 g/L and 27.83%, respecti vely.