Analysis and evaluation of growth parameters for optimum production of polyhydroxybutyrate (PHB) by Bacillus thuringiensis strain CMBL-BT-6

Synthetic polymers obtained from petrol causes air pollution only because they are not degraded in soil for a long time. for this reason,a microbial plastic poly-β-hydroxybutyrate (phb) has gained importance since it can be easily degraded in nature. phb is a widely distributed intracellular reserve substance typical of prokaryotes. phb exists in the cytoplasmic fluid in the form of crystalline granules about 0.5 μm in diameter and can be isolated as native granules or by solvent extraction. the study aimed at screening of phb producing strain and optimizing media parameters for increased phb production by a bacillus thuringiensis strain cmbl-bt-6,which was identified as phb producing strain by staining with sudan black b dye. conditions for best phb production were optimized. maltose was found to be best carbon source and ammonium nitrate the best nitrogen source producing 0.867g/l and 0.953g/l of phb,respectively. glucose was used as a substrate and 4% glucose concentration (0.953g/l) was found to be best for phb production. the data further indicated that cmbl-bt-6 produced 2.75g/l phb at ph 7.0,when incubated at 37°c for 24 h. © 2014 zoological society of pakistan.