预处理沙柳酶解液脱毒及其丁醇发酵

Butanol production from detoxified Salix hydrolysate

为了提高沙柳原料的丁醇发酵效果,考察沙柳原料经过蒸爆、超微粉碎+稀酸和超微粉碎+稀碱预处理后补料酶解的效果,优化了沙柳酶解液活性炭脱毒工艺参数,并对经过脱毒处理的酶解液进行了丁醇发酵研究,结果表明:预处理沙柳原料酶解底物质量浓度为200 g/m L时,3种预处理方法中蒸爆处理法水解效果最好,每克底物的滤纸酶酶加量15 U,酶解96 h后,酶解液总糖质量浓度达到57 g/L。活性炭脱毒处理的最优条件:p H 4.8,碳加量4%(质量分数)、温度70℃、1 h,该条件下的沙柳水解液脱色率达到97.4%、糖损失率3.1%。3种预处理沙柳原料的酶解液经活性炭脱毒后都可以被丁醇梭菌正常利用发酵产丁醇,发酵液总溶剂(ABE)质量浓度约为14 g/L。

In this study, we studied methods to improve butanol fermentation of Salix hydrolysates after pretreatment and enzymatic hydrolysis. Salix samples were pretreated by steam explosion, ultrafine grind with dilute acid and uhrafine grind with dilute alkali, respectively. Before acetone-butanol-ethanol （ABE） fermentation, we optimized the feeding enzyme hydrolysis and activated carbon detoxification. Steam explosion pretreated Salix samples had the highest sugar yield （57 g/L） after enzymatic hydrolysis, with 200 g/mL substrate consistency, 15 FPU enzyme loading for 96 hours. The optimal condition of activated carbon detoxification was observed with 4% activated carbon loading at pH 4. 8 and 70 ℃ for 1 hour. Under that condition, hydrolysate was decoloarated by 97.4% with 3.1% sugar loss. The detoxified Salix hydrolysates of three pretreatment methods could be fermented by Clostridium acetobutylicums, and the total product solvent （ABE） was about 14 g/L.