Study on High-concentration Ethanol Fermentation from Uncooked Corn Flour Based on Batch Supplement Strategy

[Objective] The propose of the study was to optimize the technology for high-concentration ethanol fermentation from uncooked corn flour.[Method] In an external circumfluent fermentor,the effects of some factors such as the initial adding amount,the initial time and the interval adding time for fermenting mash and the adding amount of fermenting mash each batch on ethanol fermentation from uncooked ground corn flour were investigated and the optimized technology was applied in high-concentration ethanol fermentation.[Result] The initial fermenting mash was prepared by adding the raw starch enzyme at 100 AUN/g according to the ratio of material to water of 1.0∶ 2.3.After that,30% of the fermenting mash and yeast seed culture were added into external circumfluent fermentor and fermented directly.Additionally,5% of the remained fermenting mash was added every 30 min after fermentation for 2 h and fermented at 30 ℃ until 72 h.The final ethanol concentration in the broth reached 120.0 g/L and the starch utilization reached 90.08%.Compared with the common ethanol fermentation process,the ethanol concentration was 15.3% higher.Furthermore,the process was applied to high-concentration ethanol fermentation from uncooked ground corn.When the ratio of material to water was 1.0∶ 1.8,the ethanol concentration in the broth and the starch utilization reached 133.6 g/L and 86.6%,resp.[Conclusion] This technology,presented by this experiment,of batch adding and strengthening circulation for ethanol fermentation from uncooked material could raise fermentation remarkably,thus increasing the ethanol concentration.