Supercritical Methanolysis Of Pretreated Rice Straw And Wheat Straw With White-rot Fungi

In this research,the supercritical methanolyses of pretreated rice straw and wheat straw with white-rot fungi were studied,and the possible effect mechanism of pretreatmentwith white-rot fungi on supercritical methanolysiswas persumed by the supercritical methanolyses of microcrystalline cellulose,xylan and alkaline lignin.The experiment discusses the influence of different pretreatment time on the yield of soluble portion from supercritical methanolysis of rice straw or wheat straw.Due to experiments,the optimized reaction conditions were wood determined.The chemical compositions of methanol soluble portion were analyzed by FTIR,GC/MS and FTICRMS.The raw and pretreated rice strawandwheat straw were characterized by FTIR,SEM,XPS,XRD and thermogravimetric analysis.Results showed that,the optimization condition for supercritical methanolysis of rice straw is that the pretreatment time is 10 days,reaction temperature is 260 oC,and the reaction time is 30 min.The optimization condition for supercritical methanolysis of wheat straw is that the pretreatment time is 5 days,reaction temperature is 260 oC,and the reaction time is 30 min.The soluble portions from supercritical methanolysis were analyzed by FTIR and GC/MS.The results indicated that the chemical components of soluble portion from supercritical methanolysis of sraws were complicated.Meanwhile,the mainly constituents included esters,ketones,phenlic and ethers compounds.In addition,the pretreatment time had some effect on the distinction of constituents from biomass,and could raise the yield and conversion specificity of esters and improve the generation of the long-chain carboxylic acid esters,especially methyl palmitate,methyl(9Z,12Z)-octadeca-9,12-dienoate and methyl(E)-octadec-11-enoate.The soluble portions from supercritical methanolysis were analyzed by ESI FTICRMS.The results indicate that the kinds and contents of oxygen-containing and nitrogen-containing compounds from in methanol soluble portion from pretreated straw were different with that from raw straws.The pretreatment could improve the conversion of oxygen-containing and nitrogen-containing compounds.The FTIR,SEM,XPS,XRD and thermogravimetric analyses of raw and pretreated straws show that the structure of the bomass was decomposed incompletely with minimal loss of carbohydrates.The supercritical methanolyses of microcrystalline cellulose,xylan and alkaline lignin with different pretreatment time were performed,respectively.Thought the comparative of soluble portion yield,the results showed that supercritical methanolysis of pretreated microcrystalline cellulose and xylan were better than that of raw microcrystalline cellulose and xylan,and supercritical methanolysis of pretreated lignins were similar with that of raw lignin.The GC/MS analysis showed pretreatment could improve the chemical composition of methanol soluble portion of microcrystalline cellulose and xylan.However,the pretreatment had no effect on the chemical composition of methanol soluble portion of lignin.Thepossible effect mechanism of pretreatmentwith white-rot fungi on supercritical methanolysis was presented.