Production of PHB by a Bacillus megaterium strain using sugarcane molassesand corn steep liquor as sole carbon and nitrogen sources

Poly(hydroxybutyric acid) (PHB) and other biodegradable polyesters are prom ising candidates for the development of environment-friendly, totally biode gradable plastics. The use of cane molasses and corn steep liquor, two of t he cheapest substrates available in Egypt, may help to reduce the cost of p roducing such biopolyesters. In this work, the effect of different carbon s ources was studied. Maximum production of PHB was obtained with cane molass es and glucose as sole carbon sources (40.8, 39.9 per mg cell dry matter, r espectively). The best growth was obtained with 3% molasses, while maximum yield of PHB (46.2% per mg cell dry matter) was obtained with 2% molasses. Corn steep liquor was the best nitrogen source for PHB synthesis (32.7 mg p er cell dry matter), on the other hand, best growth was observed when ammon ium chloride, ammonium sulphate, ammonium oxalate or ammonium phosphate wer e used as nitrogen sources.