Pretreatment Of Sugarcane Bagasse Based On NaOH-ethylene Glycol Mixture

Bagasse is rich in cellulose and can be fermented to fuel ethanol after enzymatic hydrolysis,which could not only solve environmental pollution issuse,but also alleviate the fossil energy crisis.However,because of the complex,and dense structure of bagasse,pretreatment process is needed to destroy bagasse to improve the efficiency of enzymatic hydrolysis and fermentation.In this work,to reduce the usage of strong alkali,an efficient pretreatment method using Na OH-ethylene glycol mixture was developed.The optimal pretreatment conditions were optimized,and its mechanism of action were preliminary discussed.(1)The effect of different concentrations of ethylene glycol on bagasse pretreatment was studied,and the optimal concentration of ethylene glycol was 60%(v/v).(2)The single factor method and the response surface analysis were used to optimize the pretreatment system for ethanol production.The results showed that the maximal total fermentable sugar concentration reached 17.38 g/L when bagasse was pretreated by 1%Na OH and 76.75%(v/v)ethylene glycol concentration at 198 ? for 2 h;the maximum yield of total fermentable sugar was 0.53 g/g when bagasse was pretreated by 1%Na OH and 40%(v/v)ethylene glycol concentration at 200°C for 2 h.(3)The bagasse pretreated with the above two conditions were used as substrates for the separate enzymatic hydrolysis and fermentation(SHF).The highest ethanol concentrations were 4.907 g/L and 4.997 g/L,and the ethanol yields were 153.06 g/kg and 146.48 g/kg,respectively,which were significantly higher than those from bagasse pretreated with 2% Na OH.(4)Compared to the untreated bagasse,the surface of bagasse pretreated with Na OH-ethylene glycol was rough and fluffy,and with more irregular gaps,which would increase the accessibility of cellulases to bagasse and improve the efficiency of enzymatic hydrolysis.The characteristic peaks of carbohydrates of pretreated bagasse were significantly enhanced,while the characteristic peaks of lignin were significantly weakened.The overall results indicated that Na OH-ethylene glycol mixture pretreatment method could effectively remove the lignin while reduce the usage of strong alkali,which was of economic benefits for biomass utilization.