Studies On The Process Of Schweizer Reagent Pretreatment Over Corn Stover Biomass

Due to its convenience of producing,transporting,storing and mixing with other fossil fuels,cellulosic ethanol,produced with lignocellulosic biomass,has great potential to replace traditional fossil fuels.Since the development of second-generation fuel ethanol,people have been devoting to finding a pretreatment method that effectively destroys the dense cross-linked structure of biomass and significantly removes lignin.In this study,the author developed a new pretreatment method with Schweizer reagent(SR),optimized its pretreatment conditions,enzymatic hydrolysis and fermentation process,and obtained the following results:(1)The optimal condition of SR pretreatment was:140?,60 min and 10% solidliquid ratio,which resulted in high sugar enzymatic yield(glucose,more than 87.0%;xylose more than 31.1%)and high lignin removal rate(84.47%).SEM,FT-IR,XRD spectra characterization of the structure of corn stalk before and after pretreatment showed that the dense cross-linked structure of cellulose,hemicellulose and lignin was effectively destructed.(2)The optimal condition of simultaneous saccharification and co-fermentation(SSCF)process of SR-pretreated corn stover by orthogonal test was: 34?(fermentation temperature),12h(pre-enzymolysis time),5 g/L(inoculation amount),p H 5.5.By using mixed culture fermentation strategy,the optimal temperature of enzymatic hydrolysis and fermentation reached a balanced value,and ethanol concentration has remarkably increased,which played a positive role in SSCF process.Additionally,this article compared with the effects on SSCF of three reducing agentssodium dithionite,sodium sulfite and sodium trifluoromethanesulfinate.And the addition of reducing agent could weaken the inhibitory effect of aldehyde compounds on the enzymatic hydrolysis and fermentation process where sodium dithionite in SSCF fermentation system obviously promoted the production of ethanol concentration.(4)Compared with GPC,FT-IR and HSQC spectra characterization of cellulolytic enzyme lignin and SR-pretreated lignin,the results indicated that the molecular weight of lignin has reduced,some feature bonds of lignin such as ?-O-4 and 5-5'were ruptured and the connections of p-coumaric and ferulic acid of LCC were significantly reduced,which showed that the lignin had been distinctly removed and degraded after SR pretreatment.