过氧化氢-乙酸联合预处理对甘蔗渣酶解和发酵的影响

采用过氧化氢-乙酸(HPAC)对甘蔗渣(SCB)进行了联合预处理。以预处理后的甘蔗渣为原料, 先进行酶水解, 然后将水解液进行乙醇发酵, 探讨预处理对甘蔗渣酶解和发酵的影响。实验结果表明: 20 g甘蔗渣, 加入150 mL过氧化氢水溶液(75 mL过氧化氢(30%)和75 mL水)和150 mL乙酸(99%), 硫酸用量为过氧化氢-乙酸溶液体积的0.5%, 在70 ℃反应2 h时, HPAC预处理脱除了88.85%的木质素, 并使90.10%的纤维素保留在底物中。底物(HPAC/70-SCB-0.5)的酶可及度是80.30 mg/g, 与相同条件下单独过氧化氢预处理(HP/70-SCB)和单独乙酸预处理(AC/70-SCB)相比, 分别增加了38.26%和31.08%, 甘蔗渣木质素的表面覆盖率从原料的0.66降低至0.22。酶解上清液在酶用量为5 FPIU/g(以底物计)条件下水解后, 葡萄糖得率是87.63%, 分别是HP/70-SCB和AC/70-SCB的6.89和20.62倍, 发酵产乙醇质量浓度是7.57 g/L, 分别是HP/70-SCB和AC/70-SCB的7.65和22.94倍。

Effect of Hydrogen Peroxide-acetic Acid Pretreatment on Enzymatic Hydrolysis and Fermentation of Sugarcane Bagasse

Sugarcane bagasse(SCB) was pretreated by hydrogen peroxide-acetic acid(HPAC). The pretreated SCB was used as raw material for enzymatic hydrolysis, and then the hydrolysate was fermented for ethanol. The effects of pretreatment on enzymatic hydrolysis and fermentation of SCB were discussed. The results showed that HPAC pretreatment removed 88.85% lignin and retained 90.10% cellulose in the substrate when 20 g SCB was added with 150 mL aqueous hydrogen peroxide(i.e., 75 mL hydrogen peroxide(30%) and 75 mL water) and 150 mL acetic acid(99%), the amount of sulfuric acid was 0.5% of the HPAC solution volume, and the reaction was preformed at 70 ℃ for 2 h. The enzyme accessibility of substrate was 80.30 mg/g, which increased by 38.26% and 31.08% compared with those of hydrogen peroxide pretreatment (HP/70-SCB) and acetic acid pretreatment(AC/70-SCB) under the same conditions, respectively, and the surface coverage of lignin decreased from 0.66 to 0.22. After hydrolysis with enzyme dosage of 5 FPIU/g(substrate), the yield of glucose was 87.63%, which was 6.89 and 20.62 times than those of HP/70-SCB and AC/70-SCB, respectively. The mass concentration of ethanol produced by fermentation was 7.57 g/L, which was 7.65 and 22.94 times than those of HP/70-SCB and AC/70-SCB, respectively.