Abstract: In order to express the glucoamylase gene efficiently with Saccharomyces cerevisiae S78 as a host strain and to further expand the application of glaA gene in industrial production.The glaA gene was cloned from Aspergillus niger by RT-PCR,and the sequence removed the natural signal peptide coding region was recombined into the downstream of the yeast expression vector pVT102U/α ADH1 strong promoter and fused with the sequence of α factor secretion peptide signal.The recombinant expression vector was transformed into Saccharomyces cerevisiae S78 strain by PEG/LiAc method.The selected transformants were spread on soluble starch plates and the expression of recombinant genes was identified by iodine staining.The yeast transformants of the typical hydrolytic circles were identified and the transformants were inoculated into YPD medium.The molecular weight of the target protein about 80 kDa was detected by SDS-PAGE.The supernatant was detected by DNS method and the highest activity of enzyme was 28.86 IU/mL in normal bottle fermentation.It indicated that the glucoamylase gene had been successfully expressed in Saccharomyces cerevisiae S78 and the enzyme could be effectively secreted.

Key words: Aspergillus niger, Glucoamylase, Saccharomyces cerevisiae, Heterologous expression

CLC Number: 

• Q78