Efficient, galactose-free production of Candida antarctica lipase B by GAUO promoter in △gal80 mutant of Saccharomyces cerevisiae

摘要

An efficient yeast gene expression system with GAL10 promoter that does not require galactose as an inducer was developed using △gal80 mutant strain of Saccharomyces cerevisiae. We constructed several combinations of gal mutations (△gal1, △gal80, △mig1, △mig2, and △gal6) of S. cerevisiae and tested for their effect on efficiency of recombinant protein production by GAL10 promoter using a lipase, Candida antarctica lipase B (CalB), as a reporter. While the use of △gal1 mutant strain required the addition of a certain amount of galactose to the medium, △gal80 mutant strain did not require galactose. Furthermore, it was found that the recombinant CalB could be produced more efficiently (1.6-fold at 5 L-scale fermentation) in △gal80 mutant strain than in the △gal1 mutant. The △gal80 mutant strain showed glucose repressible mode of expression of GAUO promoter. Using △gal80 mutant strain of S. cerevisiae, CalB was efficiently produced in a glucose-only fermentation at volumes up to 500 L.