Production of polyhydroxyalkanate (PHA) from waste cooking oil using pseudomonas oleovorans

Abstract

Polyhydroxyalkanoates (PHAs) are biodegradable polyesters which are stored in bacterial cell cytoplasm as reserve materials for carbon and energy. One of the main problems of plastics is that they have resistance to biological breakdown that result in accumulation in the environment. Bacteria synthesize and accumulate polyhydroxyalkanote (PHA) as carbon source under limiting conditions of nutrients. In this study, the bacteria, P. oleovorans was studied for its ability to produce PHA in the minimal basal medium supplemented with glucose as carbon source and (NH4)2SO3 as nitrogen source that was grown at 25oC. The functional groups of the extracted PHA granules were identified as a C=O group by Fourier Transform Infrared (FTIR) spectroscopy analysis. The drastic absorption band at approximately 1720 cm-1 indicated the stretching vibration of the C=O groups in the PHA polyester. The influence of different carbon sources, nitrogen sources, pH and inoculums on PHA production was investigated. The production optimization of PHA was done by RSM (Response Surface Method) through various growth parameters. After optimization obtained the best condition of productivity in range are pH 5.9, carbon source 93.4419 g/l, inoculums size 2.07% and nitrogen source 101.691 g/l. Also the highest PHA production after optimization is 2.28236 g/L with a desirability of 0.986 g/l, meanwhile the highest amount of PHA produced from P. oleovorans was 2.30 g/l.