A kinetic study of polyhydroxybutyrate production on nitrogen limited medium using Bacillus subtilis MTCC 9763 through a two stage cultivation strategy

作者：Muralidharan R; Radha K V^*

来源：Journal of Environmental Biology, 2015, 36(3): 537-542.

• Industrial effluents
• Kinetic model
• Logistic equation
• Poly-beta-hydroxybutyrate
• Sodium hypochlorite

In this study, a two-stage cultivation strategy was adopted for the production of Poly-beta-hydroxy butyrate (PHB), using Bacillus subtilis MTCC 9763. The culture conditions for PHB production by Bacillus subtilis MTCC 9763 were optimized with different carbon, nitrogen sources, temperature, pH and incubation time. Glucose showed a maximum of 73 mg l(-1) (12.56%) yield out of the carbon sources used, whereas peptone gave 81 mg l(-1) PHB (14.72%) for nitrogen source. The optimized condition observed for PHB production was 42 hr of incubation time with a temperature of 37 degrees C and pH 7. A two stage cultivation strategy was approached. Nitrogen source was limited in the production medium with various concentrations (25%, 50%, 75% and 100%) for enhanced production of PHB. Product yield was doubled when the nitrogen concentration was completely limited as compared with 75% of limitation with an yield of 93 mg l(-1) (20.26%). PHB was characterized using Infra Red spectroscopy. A kinetic model that describes microbial growth, cell concentration and biopolymer production was used to predict the performance of batch fermentation of Bacillus subtilis MTCC 9763. The experimental data was also fitted with the logistic equation that could provide adequate description for PHB synthesis. The present investigation revealed that industrial effluents could also be used for effective production of PHB so as to greatly reduce the risk of production cost.

• 出版日期2015-5