绿液预处理麦秆纤维素酶水解的研究

Enzymatic Hydrolysis of Wheat Straw Pretreated by Green Liquor

研究了绿液预处理对麦秆酶水解的影响。比较了不同绿液预处理条件下麦秆的浆得率、成分组成与纤维素酶解率,结果表明,预处理条件越剧烈,原料损失越大,而木质素脱除率越高,且在相同酶水解条件下,纤维素酶解率却越高,其中适宜的条件是预处理温度150℃,总碱量8%(Na2O计,对绝干原料)和硫化度40%,浆得率62.0%,葡聚糖、木聚糖和木质素质量分数50.0%、18.9%和16.2%,葡萄糖和木糖得率分别为74.2%和73.5%。考察了质量浓度和酶用量对绿液预处理麦秆酶水解的影响,优化了商品纤维素酶酶系结构和Tween-80的添加量,表明绿液预处理麦秆纤维素酶水解的适宜条件为质量浓度100 g/L,纤维素酶用量15 FPU/g(以纤维素计,下同),β-葡萄糖苷酶9 IU/g,木聚糖酶30 IU/g,Tween-800.05 g/g。在以上条件下,酶水解72 h,葡萄糖得率和木糖得率分别达到了82.5%和77.8%,是优化前的2.6和1.6倍。

The wheat straw pretreated by green liquor was hydrolyzed under the exist of enzymes. The pulp yield, chemical com- position and enzymatic hydrolysis yield under different green liquor pretreatment conditions were studied. The results indicated that the pulp with higher weight loss and delignification were obtained as more severe condition was applied in pretreatment, and the enzymatic hydrolysis yield was higher in the same enzymatic hydrolysis conditions. The proper pretreatment was conducted at 150℃ as the total alkali charge and sulfidity were 8 % and 40 % while pulp yield was 62.0 % , the content of glucan, xylan and lignin was 50.0 %, 18.9 % and 16.2 %, glucose yield and xylose yield was 74.2 % and 73.5%, repectively. The effects of mass concentration and enzyme dosage on wheat straw pretratment by green liquor were investigated. The enzyme system and addition amount of Tween-80 were optimized. The optimum enzymatic hydrolysis conditions of wheat straw by green liquor were 100 g/L mass concentration, 15 FPU/g cellulase dosages, 9 IU/g β-glucosidase, 30 IU/g xylanase and 0.05g/g Tween-80. The glucose yield and xylose yield were 82.5 % and 77.8 % respectively under the optimum pretreatment conditions. They were 2.6 times and 1.6 times of those without treatment.