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

SONG Lili; HUO Shanhao; FENG Mengqi; YANG Xu; ZHANG Zhiping; ZHANG Jingnan; WEI Tao

doi:10.12187/2023.06.011

Abstract：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 fermenta-tion,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.lacte-us 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 fermenta-tion 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.