Study On Pretreatment Conditions And Enzymatic Saccharification Of Different Lignocellulose Biomass

The biorefinery technologies of biomass,is global research hotspot nowadays,aiming for replacing fossil energy to mitigate energy crisis.Lignocellulosic biomass has advantages to product bioresource for direct usage since its widespread,abundant,and renewable.How to efficiently convert lignocellulosic biomass remains the key to this kind of biorefinery.In this study,salix,corn cob,and poplar as three different kinds of lignocellulosic biomass were utilized to investigate their pretreatment and enzymolysis processes with different conditions.The resource conversion efficiency to different processes were evaluated and compared,which is conducive to conclude more efficient pretreatment methods.The content of salix,corn cob,and poplar were analyzed.Corn cob has high content of hemicellulose,which was 37.23%,and its cellulose and lignin were 24.09%and 7.29%,respectively.The hemicellulose and cellulose content of salix and poplar were comparative,which were over 25%and 30%respectively.The lignin content of them were high,which were 14%and 16%respectively.Acid pretreatment,alkaline pretreatment,and microwave pretreatment were utilized to pretreat salix,corn cob and poplar,comparing the effects of 27 kinds of pretreatments with ligincellulosic biomass.It can be concluded that the pretreatment reducing sugar yields?PRSY?of corn cob responded the best with the same pretreatment.The PRSY of salix,corn cob and poplar were all responded the highest with the acid pretreatment?2.13%H2SO4,121oC?among the three methods,which were 16.88 g/L,16.92 g/L and 36.76 g/L,respectively.The weight loss during the alkaline pretreatment were high while its reducing sugar yields were low.Facilitations of the microwave pretreatment in the salix,corn cob and poplar were not obvious.The pretreated biomass materials as well as unpretreated materials were enzymatic hydrolyzed.It revealed that the enzymolysis reducing sugar yields?ERSY?of unpretreated salix,corn cob and poplar were 156.45 mg/g,184.87 mg/g and 342.23mg/g respectively.The improvements of the acid pretreatment on enzymolysis efficiencies of poplar and salix were limited,which only works with low temperature.The microwave pretreatment obviously facilitates the enzymolysis of corn cob.The alkaline could efficiently improve the enzymolysis efficiencies of three materials,and the ERSY of poplar,salix and corn cob were 293.87 mg/g,309.47 mg/g,and 992.31mg/g,respectively.The resource conversion efficiency?RCE?to the three biomass materials were evaluated by analyzing their PRSYs and ERSYs,which analyzed the content of reducing sugar in pretreatment and enzymolysis processes to assess the pretreatment methods to various biomass and dominant material.It can be concluded that the RCE of salix and poplar responded the highest with the acid pretreatment?2.14%H₂SO₄,121oC?,which were 321.06 mg/g and 300.54 mg/g respectively.The RCE of corn cob responded the best with the alkaline pretreatment?1%NaOH,80oC?,which was 841.12mg/g.Therefore,the alkaline pretreatment is suitable for herbaceous lignocellulosic biomass,and acid pretreatment is suitable for woody lignocellulosic biomass.Corn cob can produce more reducing sugar.