温和碱法预处理甘蔗渣分步糖化乙醇发酵的研究

Bioethanol Production by Stepwise Saccharification and Fermentation of Sugarcane Bagasse by Using Mild Alkali Pretreatment

甘蔗渣是制糖工业的主要废弃物,因其来源广泛,纤维素含量高而成为一种重要的可再生生物资源。本文在对甘蔗渣成分分析的基础上,研究了温和碱法预处理甘蔗渣分步糖化乙醇发酵工艺。甘蔗渣经温和碱法预处理后采用分步糖化发酵来生产乙醇,正交设计试验表明影响甘蔗渣酶解的显著因素为酶添加量,并得到最优酶解条件:酶添加量为25 FPU/g甘蔗渣,温度为50℃,初始pH为4.9。在优化条件下,预处理甘蔗渣的酶解效率可达到74.26%。在甘蔗渣水解液中补加一定营养物后,适合酵母的生长和乙醇的发酵,发酵96 h时,乙醇产量达到39.79 g/L,发酵效率为82.70%,乙醇得率为0.48 g/g。本研究证实了温和碱法预处理甘蔗渣水解液发酵生产乙醇的可行性,为甘蔗渣预处理及用作乙醇发酵原料奠定了坚实的基础。

Sugarcane bagasse, the main waste product of the sugar industry, is an important renewable biological resource owing to its wide variety of sources and high cellulose content. Based on the cellulose content analysis, sugarcane bagasse was prepared with mild alkali, followed by stepwise saccharification and fermentation, to produce bioethanol. The results of orthogonal experiments showed that enzyme dosage significantly affected enzymatic hydrolysis, where optimal conditions for hydrolysis were as follows： enzyme dosage of 25 FPU/g sugarcane bagasse, temperature of 50 ℃, and an initial pH of 4.9. Under these optimal conditions, the enzymatic efficiency could reach up to 74.26%. Supplementation of the bagasse hydrolysate with certain nutrients facilitated yeast growth and fermentation to produce ethanol. Alter 96 h fermentation, the final ethanol concentration was 39.79 g/L, with a fermentation efficiency of 82.70% and an ethanol yield of 0.48 g/g. This study confirmed the feasibility of using mild alkali to pretreat bagasse hydrolysate for ethanol production by fermentation and demonstrated the benefit of pretreating sugarcane bagasse before use as raw material for ethanol production.