Hydrolysis Of Lignocellulosic Biomass By Pretreatment With Ionic Liquid

With the rapid growth of the world's demand for energy,researches from all over the world have focused on the biomass energy.However,the lignocellulose cannot be directly degraded by microbe or enzyme without pretreatment.In order to efficiently utilize the lignocellulose,it is necessary to develop effective pretreatment technologies.Hemicellulose,cellulose and lignin connecting to each other constitute the tough network of cell walls.Using[BMIM]Cl to pretreat biomass can effectively dissolve cellulose and break complex connection between cellulose and hemicellulose.The results showed that the maximum xylose yield from the acid hydrolysis of bagasse pith was 89.4%,the concentration was 32.74g/l.When the temperature was 110? and the concentration of sulfuric acid was 1.Owt.%,the maximum concentration of xylose reached to be 31.68g/l.Under this condition,the glucose concentration was 9.89g/l,the concentration of acetic acid was only 1.97g/l and the concentration of furfural was only 1.15g/l,which were suitable for fermentation.Ionic liquid(IL)can dissolve cellulose but rarely dissolve hemicellulose.However,hemicellulose can hinder enzymatic hydrolysis.Using both IL and acid to pretreat biomass,hemicellulose is hydrolyzed to reducing sugars and cellulose can be dissolved by IL.Using[BMIM]Cl containing 0-1.2%acid and 30%water to pretreat bagasse pith,the highest concentration of reducing sugars obtained from pretreatment process reached to 30.1g/l.The bagasse pith residue was used to get glucose in enzymatic hydrolysis.Pretreatment of bagasse pith with[BMIM]Cl solutions containing 1.0%HC1 at 120? for 30 min resulted in the glucose concentration of 92.3 g/1 and yield of 94.5%after 72 h of cellulase hydrolysis.The maximum yield of total reducing sugars reached to 89.9%after pretreatment and enzymatic hydrolysis.The hydrolysis of cellulose is more difficult compared with hemicellulose.Pretreatment with IL can accelerate hydrolysis of cellulose to total sugars.Therefore,the reside obtained from pretreatment with IL was hydrolyzed by one-step acid hydrolysis.Under the condition of the 150?,1.2%acid concentration and 20minreaction time,the total sugars concentration and yieldis57.58 g/land 72.6%respectively.Under this condition,there was 2.67g/l acetic acid,2.82g/l furfural,0.97g/l 5-HMF,0.67g/l levulinic acid in the hydrolysate.