碱性亚硫酸盐耦合低压蒸汽预处理对慈竹转化乙醇得率的影响

Effect of alkaline sulfite coupling low pressure steam pretreatment on ethanol production from bamboo(Neosinocalamus affinis)

慈竹是转化生物质燃料及化学品的理想原料之一。笔者采用优化的碱性亚硫酸盐耦合低压蒸汽爆破(ALS-SE)"一步法"对原料慈竹进行预处理,在脱除木质素的同时,降低碳水化合物的降解,提高转化乙醇的效率。红外光谱分析表明,ALS-SE预处理液体中含有木素磺酸盐,将其回收用作表面活性剂加入同步糖化发酵试验中,能有效降低木质素对酶的无效吸附,改善发酵效率。试验分别研究对比了底物质量分数5%和10%,纤维素酶用量18 U/g-纤维素和24 U/g-纤维素以及ALS-SE预处理液对慈竹转化乙醇的影响。结果表明,"一步法"预处理慈竹可以显著地提高乙醇得率:底物质量分数5%、纤维素酶用量18 U/g-纤维素时"一步法"预处理慈竹乙醇得率达到其理论得率的6322%,相比原料慈竹和低压蒸汽爆破,慈竹的乙醇得率分别提高了118倍和062倍;提高底物质量分数为10%,纤维素酶用量为24 U/g-纤维素,其乙醇得率提高到8214%,加入ALS-SE预处理液体时乙醇得率进一步提高到8529%,同时降低了发酵副反应的发生。

Bamboo （ Neosinocalamus affinis） is one of the ideal materials for the production of biofuels and chemicals. In this paper, a ＂one-step＂ method, namely the alkaline sulfite pretreatment coupling low pressure steam （ALS-SE）, was used to pretreat raw matarials （RM） to increase delignification as well as protect carbohydrates from degradation, and thus to improve the ethanol fermentation efficiency. Infrared spectrum analysis showed that ALS-SE pretreated liquid con- tained lignosulfonate. It was added as a surfactant to the simultaneous saccharification and fermentation （SSF）. The re- suits showed that it effectively reduced the enzyme ineffective adsorption to the lignin and improved the fermentation effi- ciency. The effect of different substrate mass fraction （5% and 10%）, enzyme loading （18 U/g-cellulose and 24 U/g- cellulose） and ALS-SE pretreated liquid on the ethanol yield were investigated and compared. The results indicated that the ＂one-step＂ pretreatment could significantly increase the ethanol yield of 63.22% at its theoretical yield with the sub- strate mass fraction of 5% and the cellulase amount of 18 U/g-cellulose. This yield was about 1.18 and 0. 62 times high- er compared with the RM without pretreatment and with low pressure steam explosion （SE） treatment. The ethanol yield of 82. 14% was achieved by increased the substrate mass fraction of 10% and cellulase dosage of 24 U/g-cellulose ; The conversion rate of ethanol was futher increased to 85.29% with the addition of ALS-SE pretreated liquid as a surfactant. At the same time, the happening of side reactions of Neosinocalamus affinis in SSF was reduced.