Study On Ethanol Fermentation With Uncooked Corn Flour In External Circumfluent Fermentor

Nowadays the energy sources supply is increasingly serious in china .It is urgent to develop substitute for petroleum, and fermentative ethanol is one of substitute candidates with greatest future potential for its reproducibility .The ethanol production with non-cooking process has been paid attention to because both energy consumption and equipment investment could be reduced. Very High-Gravity(VHG) ethanol fermentation can increase plant capacity and efficiency, decrease the labor costs and the consumption of energy, and reliever the load of distiller's grain disposal .VHG has a bright application future. If combining these two technologies, we can possibly establish an efficient and clean alcohol production.Compulsory circulation could effectively alleviate the adverse effects of precipitation after the start-up phase fermented corn flour sop up. Through the estimates of Q₁=(U₀Ae/(C₀-e)) and test, when using the circle means 1, critical flow was 47 mL / min, while using the circle means 2, the critical flow was 31 mL / min. Take energy consumption, alcohol and starch utilization into account, we initially set up the process of fermentation process as follow: 0 8 h the use of 1, 8 72 h the use of 2.Based on compulsory circulation, partial supplement can improve the efficiency of fermentation. To prepare for the initial culture medium, ground corn was dispensed in the water with constant agitation until the final ratio of ground corn to water was 1:2.3 (w/v) and then 100 U glucoamylase per gram corn was added. After that, 30 % of the mixture and yeast seed culture were added into the reactor and fermented directly. Additionally, 5 % of the remained mixture was fed every 30 min after 2 hour's fermentation and fermented at 30 oC until 72 h. The results showed that the ethanol concentration in the broth reached 120.0 g/L and the utilization rate of starch reached 90.08 %. Compared with the common ethanol fermentation process from uncooked ground corn, the ethanol productivity was 15.3% higher. Furthermore, the process was applied to very high gravity (VHG) ethanol fermentation from uncooked ground corn. When the ratio of ground corn to water was 1:1.8 (w/v), the ethanol concentration in the broth and the utilization rate of starch reached 133.6 g/L and 86.6 %, respectively.Furthermore, the partial supplement technology was scaled up on 15 L compulsory circulation of fermentor. When the ratio of ground corn to water was 1:2.3 (w/v), the ethanol concentration in the broth and the utilization rate of starch respectively reached 118.5 g/L and 89.12 %, to achieve the level of industrial production; When the ratio of ground corn to water was 1:1.8 (w/v), the ethanol concentration in the broth was 129.9 g/L. Although the utilization rate of starch was 85.05%, this process is able to raise the equipment utilization rate, reduce environmental pollution, and realize the high efficiency fermentation.