High expression and efficient secretion of Rhizopus oryzae glucoamylase in the yeast Saccharomyces cerevisiae

The expression and secretion of Rhizopus oryzae glucoamylase were studied in the yeast Saccharomyces cerevisiae. Rhizopus oryzae glucoamylase was highly expressed and efficiently secreted into a medium to a high level (above 300 mg/l) under control of a promoter of a highly expressed yeast gene, glyceraldehyde 3-phosphate dehydrogenase (GAPDH) gene, and the original signal sequence. Excess expression of the secretable glucoamylase with high copy number plasmid slightly decreased growth of the transformant cells in glucose medium but not in fructose medium.