Use of bacteriostatic antibiotics for the optimization of new media in view of supplementing POME as an alternative carbon source for PHA production - a statistical approach

Abstract

Abstract Polyhydroxyalkanoates (PHA) are among the available biodegradable plastics in the market today. However, production of biodegradable plastics cost twice as much as when compared with the production of petrochemical-based synthetic polymers due to the use of substrate costing more than 50% of the total production cost. To curb this problem, alternative renewable and cheap carbon sources are in need. The choice of renewable and cheap carbon source, in this study was palm oil mill effluent (POME). The ultimate aim of this research is to apply the use of bacteriostatic antibiotics for the optimization of new media in view of supplementing POME as an alternative carbon source for PHA production by applying statistical approach. Prior to this, isolated strains were screened for amylolytic, cellulolytic and PHA accumulation. Two potential strains selected for further optimization. The statistical software Design Expert, a new media composition was constructed which includes POME as the carbon source and Clindamycin as the metabolic inhibitor. Strain PHA-11 was able to accumulate the highest PHA concentration of 0.134 g/L under media composition of 1.2 mg/L of Clindamycin, 200 ml/L media of POME, 0.5 g/L of (NH4)2SO4 (N) and 1.5 g/L of K2HPO4-KH2PO4 mixture (P/K). On the contrary, strain PHA-17 was able to accumulate the highest PHA concentration of 0.138 g/L under media composition of 1.2 mg/ml of Clindamycin, 200 ml/L media of POME, 1.5 g/L of (NH4)2SO4 (N) and 1.5 g/L of K2HPO4-KH2PO4 mixture (P/K). The polymer content and the copolymer composition were further confirmed by HPLC analysis.