Pretreatment technology of high-gravity ethanol fermentation using fresh cassava

In order to obtain hydrolysate economically for ethanol preparation by high-gravity fermentation using fresh cassava,the pretreatment conditions aimed to increase the total sugar concentration were investigated. Base on single factor and orthogonal experiments,the optimum liquefaction conditions were established as follows: solid-liquid ratio 1 ∶ 1. 1,p H 6. 2,incubating 75 minutes above90 ℃,and 4 U / g enzyme amount. Under the conditions,the yield rate of liquefied cassava solid in hydrolysate was 93. 8%. When fresh cassava was mixed with the hydrolysate by 1∶ 1. 2 and crushed together,a fresh cassava slurry with total sugar concentration of 22%( w / v) was obtained. Using the slurry as raw materials,the fermenting mash reached 13. 1%( v / v). Conclusion: the pretreatment process could effectively increase the total sugar concentration in fresh cassava fermented mash,which was very useful in high-gravity fermentation.