Expression of Sulfolobus solfataricus P2 β-galactosidase in Bacillus subtilis and study of immobilization

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  • 1(State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China) 2(School of Biotechnology and Key Laboratory of Industrial Biotechnology Ministry of Education, Jiangnan University, Wuxi 214122, China) 3(Joint Laboratory for International Cooperation in Food Safety by the Ministry of Education, Jiangnan University,Wuxi 214122, China)

Online published: 2018-08-30

Abstract

A Sulfolobus solfataricus P2 β-galactosidase mutant F441Y was constructed, which has the characteristics of high trans-galactosyl activity and good thermostability. In this study, β-galactosidase mutant F441Y was successfully expressed in Bacillus subtilis and the fermentation process was optimized. After 80 h fermentation in 3 L fermentor, the intracellular enzyme activity reached 76.5 U/mL. Since β-galactosidase is expressed intracellularly, it was immobilized to increase the enzyme usage efficiency and reduce the cost. The immobilization of recombinant β-galactosidase cells was performed using 2% sodium alginate and 1% gelatin as carrier, 2% calcium chloride as curing solution, and 0.5% glutaraldehyde as cross-linking agent. The enzyme activity recovery rate of the cell immobilization reached 62%. Using the immobilized cells for lactose enzyme conversion, the highest conversion of galactooligosaccharides was up to 55.1% after optimizing the conversion conditions.

Cite this article

LIU Dong-bin et al . Expression of Sulfolobus solfataricus P2 β-galactosidase in Bacillus subtilis and study of immobilization[J]. Food and Fermentation Industries, 2018 , 44(7) : 37 -43 . DOI: 10.13995/j.cnki.11-1802/ts.016796

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