Effect Of Pretreating With Acetone And Ethanol On Enzymatic Saccharification Of Rice Straw

There is lignin in lignocelluloses. Lignocelluloses is difficult to hydrolysis into sugar by enzymes or microbe because it has a larger the degree of crystalline. Rice straw was pretreated with acetone-phosphoric acid organosolv pretreatment, ethanol-phosphoric acid organosolv pretreatment, ethanol-FeCl3 organosolv pretreatment, and then hydrolyzed with cellulose to produce glucose. The results showed that the crystalline structure of rice straw was destroyed with organosolv pretreatment, the specific surface area and porosity were increased. Surface of the pretreated straw became into porous structure, and was easily hydrolyzed by hydrolytic enzymes and microbe. The pretreatment process can improve the enzymatic saccharification ratio of straw.Rice straw was pretreated with acetone-phosphoric acid mixture at 60℃, 50%(v/v) acetone for 1 h. Enzymatic hydrolysis ratio of rice straw increased from 10.03% to 62.46%. The enzymatic saccharification ratio of the pretreated straw increased with the particle size decreased. Rice straw was pretreated with ethanol-phosphoric acid mixture at 50℃, 50%(v/v) ethanol for 1 h. Enzymatic hydrolysis ratio of rice straw increased from 10.03% to 57.75%t.The saccharification ratio of the pretreated rice straw with acetone-phosphoric acid was close to that with the reused acetone-phosphoric acid, and were respectively 58.9% and 53.88%. The saccharification ratio of the pretreated rice straw with ethanol-phosphoric acid was close to that with recycled ethanol-phosphoric acid, and were respectively by 57.75% and 56.89%. It was shown that the recovery mixed solution in the pretreatment process and be reused as pretreating agent. After pretreatment, organic solvent, lignin, phosphoric acid and other useful materials were easily recycled by distillation, centrifugation and filtration.Enzymatic hydrolysis ratio of rice straw increased from 10.03% to 65.91% when rice straw was pretreated with ethanol-FeCl3 organosolv pretreatment at 70℃for 1 h. Increasing the pretreatment temperature can reduced the pretreatment time.