鲜甘薯发酵生产燃料乙醇中的降粘工艺

鲜甘薯高浓度发酵生产燃料乙醇的瓶颈之一是醪液粘度高,容易堵塞管路,严重影响工业化生产和增加能源消耗,同时也会降低乙醇发酵效率.为解决此问题,进行了添加降粘酶系及其作用条件优化研究,结果如下:1)确定最适降粘酶系为四川禾本生物工程有限公司的纤维素酶,粘度由1.7×104mPa.s降到8.8×102mPa.s,并且降低了生产成本;2)确定降粘酶作用前高温处理条件:110℃,20 min;3)最适降粘酶对不同品种鲜甘薯高浓度发酵的降粘效果表明降粘酶对大部分品种鲜甘薯降粘效果较好,粘度均约为1.0×103mPa.s以下,最低粘度只有2.7×102mPa.s,粘度下降率均在95%以上;4)在确定最适降粘酶系和其作用前高温条件后,将其应用于工业化生产,加入降粘酶2 h后发酵醪液的粘度由1.8×105mPa.s下降到2.7×103mPa.s,发酵后终粘度仅为7.9×102mPa.s,发酵时间仅为23 h,乙醇浓度达到10.56%(V/V),进一步验证了该降粘酶系应用于工业化鲜甘薯燃料乙醇生产的实际意义.表8参19

Viscosity Reduction During Fuel Ethanol Production by Fresh Sweet Potato Fermentation

Fresh sweet potato is one of the major feedstocks for fuel ethanol production in China.However,high-viscosity syrup is the key factor affecting high gravity fermentation of fresh sweet potato.It easily leads to pipe block,which seriously reduces the ethanol fermentation efficiency,influences the industrial production of ethanol with fresh sweet potato and increases the energy consumption.In this paper,the experiments on the viscosity-reducing enzyme and its optimized conditions were carried out,and the results showed that:(1) The cellulase from Sichuan Habio Bioengineering Co.,Ltd was the best enzyme,reducing the viscosity from 1.7×104 mPa.s to 8.8×102 mPa.s,and greatly reduced the cost of ethanol production.(2) The optimal pretreated condition was 110 ℃ for 20 min.(3) The viscosity-reducing enzyme could be applied to different varieties of fresh sweet potatoes,and the viscosity all reduced to less than 1.0×103mPa.s,with the lowest value of 2.7×102mPa.s.The viscosity reduction rates were all more than 95%.(4) Under optimal conditions,the viscosity of fermented sweet potatoes decreased from 1.9×105mPa.s to 2.7×103mPa.s after treated for 2 h by enzyme,and reduced to 790 mPa.s after fermentation of 23 h.The ethanol concentration reached 10.56%(V/V).The results were validated further that the viscosity-reducing enzyme had potential in industrial scale ethanol fermentation with fresh sweet potato.Tab 8,Ref 19