蒸汽爆破麦草同步糖化发酵转化乙醇的研究

近年来对木质生物资源同步糖化发酵转化乙醇的研究较多,但是,麦草同步糖化发酵转化乙醇的最佳工艺条件还未确定。文中采用正交试验设计的方法,对在混合酶(纤维素酶Celluclast 1.5 1,β-葡萄糖苷酶Novozym 188)与酿酒酵母菌作用下,稀硫酸催化的蒸汽爆破麦草原料同步糖化发酵转化乙醇的工艺条件进行研究,详细讨论了反应温度、底物质量浓度、发酵液pH值、纤维素酶浓度对乙醇质量浓度和得率的影响。结果表明,工艺条件对乙醇质量浓度和得率的影响程度由高到低依次为:底物质量浓度、纤维素酶浓度、发酵液pH值、反应温度。最佳工艺条件为反应温度35℃,底物质量浓度100 g/L,发酵液pH值5.0,纤维素酶浓度30 FPU/g。在此条件下,随着反应时间的延长,乙醇质量浓度持续上升。反应72 h后,乙醇质量浓度和得率分别达到22.7 g/L和65.8%。

Study of simultaneous saccharification and fermentation for steam exploded wheat straw to ethanol

Although simultaneous saccharification and fermentation(SSF) has been investigated extensively,the optimum condition for SSF of wheat straw has not yet been determined.The dilute sulfuric acid impregnated and steam exploded pretreated wheat straw was used as substrate for the production of ethanol by SSF through orthogonal experiment design.Cellulase mixture(Celluclast 1.5 1 and β-glucosidase Novozym 188) were used in combination with the yeast Saccharomyces cerevisiae AS2.1.The effects of reaction temperature,substrate mass concentration,initial fermentation liquid pH value and enzyme loading were evaluated and the SSF conditions were optimized.The ranking,from high to low,of influential extent of the SSF affecting factors to ethanol mass concentration and yield was substrate mass concentration,enzyme loading,initial fermentation liquid pH value,reaction temperature,orderly.The optimum SSF condition was 35 ℃ for reaction temperature,100 g/L for substrate mass concentration,5.0 for initial fermentation liquid pH value,30 FPU/g for enzyme loading.Under the optimum SSF condition,the ethanol mass concentration increased with reaction time,22.7 g/L of the ethanol mass concentration and 65.8% of the ethanol yield were obtained respectively after 72 h.