木薯生料发酵生产高浓度燃料乙醇工艺研究

Very High Gravity Fuel Ethanol Production with the Fermentation of Uncooked Cassava

【目的】对木薯生料发酵生产高浓度燃料乙醇的工艺进行研究,为其工业化生产奠定基础。【方法】首先通过单因素试验确定发酵中主要影响因素的最佳水平,然后利用响应面法对主要因素的相互作用进行研究,最后对发酵温度进行梯度降温控制,以提高乙醇的产量。【结果】单因素试验确定主要影响因素的最佳水平:颗粒淀粉水解酶用量为0.8GAU/g木薯粉,底物浓度为36%(W/V),初始pH值为4.2。响应面法优化的结果:颗粒淀粉水解酶用量为0.82GAU/g木薯粉,底物浓度为37%(W/V),初始pH值为4.3。对发酵温度进行梯度降温控制,则可降低醪液残糖,提高原料转化率。在技术集成基础上,对木薯生粉发酵96h,醪液乙醇产量可达16.24%(V/V),残还原糖含量为0.29%(W/V),残总糖含量为1.81%(W/V)。与初始条件相比,乙醇产量提高25%。【结论】木薯生料发酵生产高浓度燃料乙醇,在技术集成基础上可降低能耗,节约生产成本,具有较好的工业化应用前景。

【Objective】Very high gravity fuel ethanol production was studied with the fermentation of uncooked cassava flour.【Metheds】First,the important parameters were screened by single factor tests.Second,the optimum values of the parameters were obtained by response sur-face methodology. And finally,a gradient temperature control strategy was used with the optimized conditions,all of which were used to improve the ethanol concentration.【Results】The conditions optimized by single factor tests were starch hydrolyzing enzyme dosage 0.8 GAU/g cassava flour,substrate concentration 36%(W/V),and initial pH value 4.2.The optimal concentrations were determined by response surfacemethodology as follows:Starch hydrolyzing enzyme dosage 0.82 GAU/g cassava flour,substrate concentration 37%,and initial pH value 4.3.A gradient temperature control strategy could reduce the reducing sugar and imporve the fermentation efficience.Under such optimum conditions,the ethanol concentration could reach up to 16.24%(V/V),while the reducing sugar and total sugar were 0.29%(W/V)and 1.81%(W/V)correspondingly,after 96 hfermentation.The ethanol content of fermentation mashing increased 25% compared with the original condition.【Conclusion】On the basis of integration technology,very high gravity fuel ethanol production and low production cost with the fermentation of uncooked cassava flour may facilitate industrial scale application in future.