The method was modified from(Yellore and Desai 1998). 350 mg dry cells were shacked in 95% (v/v) methanol for 12 hr to remove pigments. The cells were dried at 80 oC for 10 min and were extracted twice by 150 ml chloroform at 80 ºC for 1.5 hr by shaking at 250 rpm. Chloroform in the extract was evaporated until the total volume was reduced to 0.5 ml, and then 2 ml of 99.5% hexane was added to obtain 4:1(v/v), hexane: chloroform (Ramsay et al. 1994) to precipitate PHB polymer. The PHB polymer (pellet) was harvested by centrifugation at 3,000 rpm for 1 min. The PHB polymer was washed twice in 2 ml of 99% (v/v) acetone and dried at 80 ºC for 10 min.