Effect of temperature on the no cook, very high gravity ethanol fermentation process / 生物工程学报

The effect of temperature on a very high gravity ethanol fermentation using no cook process was investigated. We found that a gradient temperature control strategy could improve the fermentation efficiency significantly, With the assistance of a new raw starch hydrolyzing enzyme and a gradient temperature control strategy, the ethanol concentration could reach up to 20% (V/V) within 90 h using commercially available dry yeast, when sorghum was used as the raw material and the dry substrate concentration was controlled at 35%.

Dry solid staging fermentation / 生物工程学报

Very high gravity (VHG) ethanolic fermentation is a new perspective technology for the fuel ethanol production. Compared with traditional hot cook process in most ethanol plants, uncooked process using milled grain slurry in combination with granular starch hydrolyzing enzymes makes high gravity fermentation much easier to control. In this study, dry solids staging technique was first time reported in uncooked process for fermentation ethanol. We further studied the difference between the new process and the batch fermentation, including different initial fermentation concentrations and different starting times. The results showed that at the same dry solid concentration of 30% and the same enzyme dose at 0.22% (W/W), the final ethanol output of new process was increased to 18.50% (V/V) from 17.06% (V/V) of the conventional process. This study demonstrated the new application of uncooked fermentation technology.