Study On SFP-AQ Pretreatment And Enzymatic Saccharification Of Wheat Straw

The population in China is large, using food or sugar as raw material to produce bio-energy will inevitably influence on food safety. Diversified raw materials is a necessary trend to develop biomass energy sources industry, developing biomass energy should not conflict with land and food,it is undisputable our basic principles. Lignocellulose resources are very rich in our country, they have a huge potential for development. If they are burned directly,not only efficiency is low, but also pollute environment. If we transform them into high energy, there will be positive significance for improving rural environment, construction of new socialist countryside and constructing a harmonious society.The influence of the wheat straw which was preprocessed by SFP-AQ on the yield of enzymolysis reducing sugars was studied in this paper.(1)In SFP-AQ pretreatment process: (a)Pulp yield decreases gradually with heightening temperature, extending holding time and increasing Na2SO3 charge, and the major factor is Na2SO3 charge among the three factors; (b) Black liquor pH raise with increasing Na2SO3 charge, black liquor pH reduce with heightening temperature and extending holding time; (c)Acid lignin, ash content and high polymeric reducing sugers decrease less comparing with that of wheat straw, more Klason lignin are removed, residue lignin become lower with increasing Na2SO3 charge; there is a linear dependence relation between pulp yield and residue lignin. (d) Increasing Na2SO3 charge play an unconspicuous part in damage of cellulose crystaline region, there is no interior relation between cellulose crystaline region and glucan,xylan and total reducing sugar.(2)The results of the yield of the wheat straw which was preprocessed by SFP-AQ on enzymolysis pentaglucose(arabinose and xylose, mainly of xylose) and enzymolysis glucose show that: the yield of enzymolysis xylose and enzymolysis glucose increase with the increase of Na2SO3 dosage in the pretreatment at first, then decreased, when the dosage of Na2SO3 is 12% the both yield reach the maximum; the yield of enzymolysis xylose and enzymolysis glucose increase rapidly with the increase of the dosage of enzymes, when enzymes dosage exceed 20FPU/g yield increase slowly; the yield of enzymolysis xylose increase rapidly with the increase of the maximum temperature and holding time, there is no clear relationship between enzymolysis glucose yield and cooking temperature and holding time. The suitable pretreatment and enzymolysis conditions for enzymolysis xylose are as follows: cooking temperature 160℃; holding time lasts 2 hour with 12% of Na2SO3 dosage; the dosage of complex enzymes is 20FPU/g at 50℃which are composited of cellulase, xylanase,β-Portuguese gather glycosidase enzymes. In addition, the enzymolysis process lasts 48h, enzymolysis xylose yield can reach up to 17.5%, percent conversion of enzymolysis xylose on xylose in wheat straw is 84.9%; The optimal pretreatment and enzymolysis conditions for enzymolysis glucose are as follows: cooking temperature is 150℃;holding time lasts 1 hour with 12% of Na2SO3 charge; the dosage of complex enzymes is 20FPU/g at 50℃which are composited of cellulase, xylanase,β-Portuguese gather glycosidase enzymes. In addition, the enzymolysis process lasts 48h and the glucose yield can reach up to 31.7%, percent conversion of enzymolysis glucose on glucose in the wheat straw is 91.6%(3)Effect of the wheat straw which was preprocessed by SFP-AQ on the yield of enzymolysis reducing sugars was studied in this paper. The result shows that the optimal pretreatment and enzymolysis conditions are as follows: cooking temperature is 150℃; heating preservation lasts 1 hour with 12% of Na2SO3 charge; The usage of complex enzymes is 20FPU/g at 50℃and the enzymes are composite of cellulase, xylanase, ? -Portuguese gather glycosidase enzymes. In addition, the enzymolysis process lasts 48h and the reducing sugars yield can reach up to 46.4%.