Optimization of poly-β-hydroxybutyrate production by halotolerant bacterial strains isolated from saline environment

Abstract

PHB is a biodegradable plastic which is becoming an environmentally friendly substitute to the synthetic plastics that are persistent and accumulate in large amounts and are non-degradable. PHB is a class of Polyhydroxyalkanoate which are similar to commercial plastics like polypropylene but with an added advantage of being biodegradable. To overcome the problem of commercializing PHB production by microorganisms because of the high cost involved, Halotolerant organisms can be used as they are easier to cultivate and do not require strict sterile conditions. In this present study PHB producing halotolerant bacterial strains were isolated from a marine environment and cultivated under saline conditions. The growth conditions of the bacterial strains were optimized for maximum production of PHB. The parameters such as pH, temperature, NaCl concentration, carbon sources, nitrogen sources and carbon and nitrogen ratio were optimized and studied. The growth conditions for each of the parameter were optimized and the PHB production was estimated for the bacterial strains under saline conditions. The optimum pH and temperature range yielded maximum PHB production of about 42 – 45 mg/100ml and 30 – 40 mg/100ml respectively. The perspective application of PHB could be in the medicinal field for manufacturing medical devices as implants for various surgeries such as dental, cranio – maxillofacial and dental surgeries.