Alcohol fermentation of starch by a genetic recombinant yeast having glucoamylase activity
✍ Scribed by Yoshitoshi Nakamura; Fumihisa Kobayashi; Makoto Ohnaga; Tatsuro Sawada
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 178 KB
- Volume
- 53
- Category
- Article
- ISSN
- 0006-3592
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✦ Synopsis
Alcohol fermentation of starch was investigated using a direct starch fermenting yeast, Saccharomyces cerevisiae SR93, constructed by integrating a glucoamylase- producing gene (STA1) into the chromosome of Saccharomyces cerevisiae SH1089. The glucoamylase was con- stitutively produced by the recombinant yeast. The ethanol concentration produced by the recombinant yeast was 14.3 g/L which was about 1.5-fold higher than by the conventional mixed culture using an amylolytic microorganism and a fermenting microorganism. About 60% of the starch was converted into ethanol by the recombinant yeast, and the ethanol yield reached its maximum value of 0.48 at the initial starch concentration of 50 g/L. The fed-batch culture, which maintains the starch concentration in the range of 30 to 50 g/L, was used to produce a large amount of ethanol from starch. The amount of ethanol produced in the fed-batch culture increased about 20% compared to the batch culture.