Starter culture were prepared by inoculating the selected strain in 100 ml GM medium and incubated on a shaker (150 rpm) at 37ºC for 48 hrs. The starter culture containing 1.5x104 viable cells/ml was inoculated (10%) to GM medium supplemented with various nutrients compositions by varying carbon sources & concentrations (glucose, fructose or acetate at 0-6 g/l), nitrogen sources & concentrations ((NH4)2SO4, NH4NO3 & NH4Cl at 0-0.2 g/l), mineral salts (KH2PO4, K2HPO4, MgSO4, CaCl2 & MnSO4 at 0-1 g/l) and vitamin (nicotinic acid, r-aminobenzoic acid, thiamine each at 0-1 mg/l, biotin at 0-0.01 mg/l or no addition of vitamin). The cells were cultivated on a shaker (150 rpm) at 37ºC under aerobic-dark condition. Growth (in term of dried cell weight, DCW), pH and PHB content were determined at the end of cultivation (60 hrs).