Studies on high concentration ethanol fermentation of raw ground corn by Saccharomyces sp. H0.

In this study, high concentration alcoholic fermentation coordinated with saccharification from raw ground corn was performed at 30 degrees C, pH 4-5, in batch culture using Saccharomyces sp. H0 which was constructed by hybridization in this laboratory and the glucoamylase preparation produced on a large scale in China. The optimal conditions for high concentration ethanol production were that the amount of the glucoamylase preparation was 300 u/g of raw ground corn, the inoculum size of the yeast was 2.7 x 10(6) cells/ml, the fermentation temperature was 30 degrees C, the starting concentration of raw ground corn was 33.0% (w/v), and the fermentation period was 70 hr. At the end of fermentation, 17.5% (v/v) ethanol was yielded, with 0.19% reducing sugar, 3.5% total sugar and 16.0% cell viability remaining in the fermented mash. In the case of 36.0% (w/v) of the initial raw ground corn concentration, the strain could produce 18.0% (v/v) ethanol, leaving 0.81% reducing sugar and 5.1% total sugar in the media. We found that the glucoamylase preparation which is usually employed for saccharification of cooked starch could be used for efficient saccharification of raw ground corn starch.