Mechanisms Of Lignins Of Bamboos That Were Pretreated By Ethanol And Fenton Oxidation Enhanced The Hydrolysis Of The Cellulose

Under the condition of over consumption of fossil resources and global warming,it is an urgent and significant task to make use of lignocellulosic biomass for sugar-based compounds and fuel ethanol.This work investigated the effect and mechanisms of milled wood lignins(MWL),ethanol organosolv lignins(EOL)and Fenton oxidized lignins(FOL)from Dendrocalamus sinicus(D)and Pleioblastus amarus(P)on enzyme hydrolysis of the cellulose.The results showed that MWL inhibited the hydrolysis of the cellulose,but the EOL and FOL enhanced hydrolyses,The addition 4 g/L milled wood lignins from Dendrocalamus sinicus(MWL_D)and Pleioblastus amarus(MWL_P),the 72 h glucose yields reduced 45.3%and 48.6%,respectively,but the addition 4 g/L ethanol organosolv lignins from Dendrocalamus sinicus(EOL_D)and Pleioblastus amarus(EOL_P),the 72 h glucose yields improved 59.2%and 60.6%,respectively.Langmuir adsorption isotherm curve exposed that EOL showed a less affinity and adsorption capacity than MWL,which reduced the unproductive adsorption of EOL and enzyme.From structural analysis of MWL and EOL,EOL have showed that ferulic acid(FA)and p-coumarate acid(PCA)units were exposed in ethanol pretreatment led to an increase in the electrostatic repulsion and the hydrophilicity of molecular surface between lignin and cellulase protein,reduced the unproductive adsorption of cellulase.The addition 4 g/L of Fenton oxidized lignins from Dendrocalamus sinicus(FOL_D)and Pleioblastus amarus(FOL_P)that the 72 h glucose yield improved 21.7%and 15.5%,respectively,and the concentration of enzyme protein increased in the hydrolyzed supernatant.Langmuir adsorption isotherm curve showed that released the unproductive adsorption of cellulase by the pretreatment of Fenton and make the cellulose to acquired more enzyme in the hydrolyses.From analysis of the surface and chemical structure,Fenton oxidation has found that lignins increased formation of C–O–and O–C=O bonds and reduced the condensing unit structure so that FOL has the high surface negative charges and hydrophilicity resulted in strong the hydrolysis of the cellulose.In this work,It will be used for reference and basic theory and studyied of lignocellulosic bio-refining that reduce the inhibition of lignin,the process and mode of lignocellulose pretreatment and enzyme hydrolysis with high substrate concentration can be explored.