Optimization of the production conditions of tri-GOS and lactosucrose from lactose and sucrose with recombinant β-galactosidase

Abstract

Few studies expressed the β-galactosidase encoding gene from L. plantarum in E. coli so far. In the present study, the recombinant β-galactosidase from L. plantarum FMNP01 was used as a catalyst in transgalactosylation to form tri-GOS and lactosucrose. In the presence of lactose and sucrose, six transfer products were formed in the transgalactosylation reaction with recombinant β-galactosidase L.pFMNP01Gal as a catalyst. Three transfer products were tri-galacto-oligosaccharides (tri-GOS), lactosucrose, and lactulose; the other three transfer products needed to be identified further. Based on a single factor test and response surface methodological approach, the optimal transgalactosylation conditions of the production of tri-GOS and lactosucrose were determined as initial sugar concentration of 50%, lactose: sucrose ratio of 1:2, enzyme concentration of 3 U/mL, and reaction time of 6 h at 50 °C resulting in a maximum tri-GOS concentration of 47.69 ± 1.36 g/L and a maximum lactosucrose concentration of 8.18 ± 0.97 g/L.

Keywords:

• Lactosucrose
• recombinant β-galactosidase
• response surface methodological approach
• transgalactosylation
• tri-GOS

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by Key Project of Basic and Applied Basic Research in Jiangmen (grant number 2021030103330007214); “Climb Program” Special Funding of Guangdong Province (grant number pdjh2022b1050).