玉米原料超高浓度酒精发酵

Very High Gravity Ethanol Fermentation Using Whole Ground Corn

以全磨玉米为原料,研究了超高浓度条件下传统工艺与生料工艺的黏度变化。采用传统工艺,在超高浓度条件下,物料的糊化、液化会变得非常困难。而采用生料工艺,黏度始终维持在合理的水平。对高浓度传统工艺和生料工艺发酵的结果进行对比,证明生料工艺可以产出更多的酒精;对超高底物浓度(35%绝对干物)生料发酵时采用温度梯度控制,使用市售酒精干酵母,在98 h内发酵醪液酒精浓度可达20%以上。

Viscosity is one key bottleneck of high gravity fermentation.The viscosity profiles of both conventional process and no-cook process are investigated using whole ground corn as the raw material.At very high dry solid concentration,it is found that during conventional hot cooking process,the gelatinization and liquefaction become very hard to handle while there is no viscosity issue for no cook process.In addition,the no cook process generate more ethanol than that from conventional process during high gravity fermentation;with the help of raw starch hydrolyzing enzymes,together with commercial dry yeast and temperature staging strategy,ethanol concentration was able to reach up to 20%（v/v） within 98h.