两段碳酸钠―氧预处理提高麦草酶水解糖化性能的研究

探讨了不同Na2CO3用量下两段碳酸钠―氧(Na2CO3-O2)预处理对麦草化学成分及酶水解效率的影响。Na2CO3-O2预处理麦草浆料得率随Na2CO3用量增大而下降,木质素脱除率随之增加。预处理后废液的pH值约为9,可有效避免碳水化合物的碱性水解和二次剥皮反应,保持较高的预处理浆料得率。预处理后浆料经过由纤维素酶、木聚糖酶和β-纤维二糖酶组合而成的混合酶水解,当预处理Na2CO3用量(以Na2O计)从12%增至18%时,预处理浆料总糖得率的增加较为显著。经20 PFU/g纤维素酶水解48 h后,总用碱量为18%的两段Na2CO3-O2预处理浆料的酶水解总糖得率为40.8%,总糖转化率为67.0%。

Two Stage Sodium Carbonate-Oxygen Pretreatment for Enzyme Hydrolysis of Wheat Straw to Produce Fermentable Sugars

In the present study,the effect of two stage Na2CO3-O2 pretreatment on the enzymatic hydrolysis of wheat straw for ethanol production has been investigated at different Na2CO3 charges.Lignin can be effectively removed with the increase of Na2CO3 charge in pretreatment while pulp yield drops with the increase of Na2CO3 charge.The low pH prevents the random hydrolysis of polysaccharide and secondary peeling reactions from occurring during the pretreatment,resulting in higher retention of polysaccharide in pulp.The pretreated materials have been hydrolyzed by the enzyme mixture of cellulase,xylanase and β-glucosidase to evaluate the improvement of sugar recovery.An obvious increment of total sugar yield is obtained while the Na2CO3 charge(as Na2O) increases from 12% to 18%.After 48 h enzymatic hydrolysis under a cellulase loading of 20 FPU/g(cellulose),the total sugar yield of two stages Na2CO3-O2 pulp pretreated by total Na2CO3 charge of 18%(as Na2O) is 40.8%,and the enzymatic hydrolysis sugar recovery reaches 67.0%.