Optimization of fermentation conditions of recombinant β-xylosidase extracellularly expressed in E. coli

Abstract:

[Objective] The fermentation conditions for production of recombinant β-xylosidase from Paecilomyces thermophila expressed in E. coli were optimized and produced in a 5 L fermentor. [Methods] Single factor experiments were used to investigate the effect of different inducers and their concentrations, initial cell density, cultivation temperature and time on the expression of recombinant β-xylosidase. [Results] The results showed that the β-xylosidase could be induced by IPTG and lactose, lactose was better than that of IPTG. Under the optimal conditions by adding 2% lactose at a initiated OD600 of 0.8?0.9 and incubation for 48 h at 33 °C, the ratio of extracellular enzyme reached over 99% and enzyme activity was 103.9 U/mL. Further optimization of the culture conditions were performed in 5 L fermentor, the highest β-xylosidase activity of 392.5 U/mL and extracellular protein concentration of 10.1?g/L were obtained after 48 h. [Conclusion] The recombinant β-xylosidase with high level production will be useful in various industrial applications.

Key words:β-Xylosidase, Extracellular, Escherichia coli, Expression optimization