烟草秸秆中的烟碱对纤维素酶活性和微生物的发酵能力有明显的抑制作用,严重阻碍了烟草秸秆的利用。采用稀硫酸对烟秆进行预浸泡,以提高烟秆预处理的即时弹射器蒸汽爆炸(ICSE)性能。预浸泡有利于打破烟草茎的顽固结构,减少尼古丁含量,以减轻对纤维素酶活性和微生物代谢的抑制,并促进酶解和乙醇发酵的性能。优化的0.8%硫酸(w/w)预吸收集成ICSE预处理可从烟草茎中去除85.54%的尼古丁;同时,酶解预处理后的烟秆总糖浓度从33.40增加到53.81g/L(烟秆干水比为1:8,w/w),乙醇浓度增加103.36%从5.95到12.10g/L的烧瓶,与单独的ICSE预处理相比。最后,在5-L发酵罐中,乙醇浓度达到最高23.53g/L,通过增加酶解过程中烟草茎的固体负载,烟草茎水解物的葡萄糖的乙醇产量达到71.40%(干烟草茎与水的比例为1:4,w/w)。这些结果达到了高效利用废弃烟秆的预期目的。
The nicotine from tobacco stalk showed obvious inhibitory effect on the activity of cellulase and fermentability of microorganisms, which seriously hinders the utilization of tobacco stalk. Dilute sulfuric acid presoak of tobacco stalk was used to enhance the performance of instant catapult steam explosion (ICSE) for tobacco stalk pretreatment. The presoak was beneficial to break the recalcitrant structure of tobacco stalk, reduce nicotine content to relieve the inhibition on the activity of cellulase and metabolism of microorganisms, and promote the performance of enzymatic hydrolysis and ethanol fermentation. The optimized 0.8% sulfuric acid (w/w) presoak-integrated ICSE pretreatment resulted in 85.54% nicotine removal from tobacco stalk; meanwhile, the total sugar concentration from enzymatic hydrolysis of pretreated tobacco stalk increased from 33.40 to 53.81 g/L (the ratio of dry tobacco stalk to water was 1:8, w/w), ethanol concentration increased 103.36% from 5.95 to 12.10 g/L in flask, compared with separate ICSE pretreatment. Finally, the ethanol concentration achieved the highest 23.53 g/L in a 5-L fermenter with the ethanol yield from the glucose of tobacco stalk hydrolysate achieving 71.40% by increasing the solid loading of the tobacco stalk in the enzymatic hydrolysis process (the ratio of dry tobacco stalk to water was 1:4, w/w). These results achieved the expected purpose of efficient utilization of discarded tobacco stalk.