乳白耙菌预处理对烟秆发酵产乳酸的影响

Effect of pretreatment with Irpex lacteus on lactic acid production from tobacco stalks

针对烟秆结构致密、尼古丁抑制作用强及纤维质糖类物质转化效率低等问题,采用乳白耙菌预处理烟秆,比较预处理前后烟秆组分和结构变化,研究乳白耙菌预处理对烟秆酶解糖化效果的影响,并进一步比较不同发酵方式下(同步糖化发酵、分批发酵)凝结芽孢杆菌发酵烟秆后乳酸的转化率。结果表明:经乳白耙菌预处理20 d后,烟秆中木质素质量分数较原料烟秆降低了44.90%,乳白耙菌可选择性地破坏木质素大分子结构,木质素苯环及侧链基团均存在不同程度的降解;乳白耙菌预处理后的烟秆纤维素可反应性提升,葡萄糖的产量为260 mg/g,较原料烟秆提高了2.25倍;相较于分批发酵,同步糖化发酵的乳酸产量较高(392.16 mg/g),乳酸转化率达到86.95%,较原料烟秆提高了3.78倍。乳白耙菌预处理可选择性降解烟秆木质素,降低烟秆酶解糖化抗性,提升烟秆乳酸的转化率。

To solve the problems of dense structure of tobacco stalk,strong nicotine inhibition and low conversion efficiency of cellulosic sugars,the tobacco stalks were pretreated with Irpex lacteus.The composition and structure changes of tobacco stalks before and after pretreatment were compared to study the effects of I.lacteus pretreatment on enzymatic hydrolysis and saccharification of tobacco stalks.The conversion rate of lactic acid from tobacco stalks fermented by Bacillus coagulans under different fermentation conditions(simultaneous saccharification fermentation,batch fermentation)was further compared.The results showed that the mass fraction of lignin in the tobacco stalks was reduced by 44.90% compared with that of the raw tobacco stalks.Biological pretreatment using I.lacteus could selectively destroy the macromolecular structure of lignin,and the benzene ring structure and side chain groups of lignin were also degraded.The reactivity of cellulose in tobacco stalks was improved after pretreatment with I.lacteus and the yield of glucose was 260 mg/g,which was enhanced by 2.25 times compared with raw tobacco stalks.Compared with batch fermentation,the lactic acid yield of simultaneous saccharification fermentation was higher(392.16 mg/g),and the conversion rate of lactic acid reached 86.95%,which was 3.78 times higher than that of raw tobacco stalks.The pretreatment of I.lacteus could selectively degrade lignin of tobacco stalks,reduce the resistance of enzymatic hydrolysis to saccharification of tobacco stalks and increase the conversion rate of lactic acid of tobacco stalks.