木薯生料发酵生产高浓度燃料乙醇工艺研究

【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。

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

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 surface 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 surface methodology 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 h fermentation.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.