In conclusion, it can be concluding that optimum culture conditions for PHB production by B. cereus. The existence of carbon source where the sugar of sucrose was considered the best carbon source to produce PHB compared to the other carbon
sources by B. cereus. In the present work, a low cost of raw material as sugarcane, molasses, whey and rice straw hydrolysate could improve the economics of the process and obtained high PHB production when 2%