In order to investigate the mechanism of PEG4000 addition on enhancement of the enzymatic hydrolysis using the acid steam-exploded corn straw( ASCS) as the raw material, its physochemical properties such as composition, BET and elemental analysis of the substrate, were studied. Based on these results, the effect of PEG on hydrolysis process was studied, and the mechanism was also explored. Moreover, structural changes of substrates before and after hydrolysis were analyzed by FT-IR and SEM. Acid steam-exploded corn straw had a high lignin content with a large BET surface area. With the dose of cellulase 15 FPIU/g (calculated by cellulose) and glucosidase 30 U/g, the glucose conversion of 50 g/L ASCS could reach 76. 4% by hydrolysis time of 24h. PEG addition could effectively improve the enzymatic hydrolysis of the acid steam-exploded corn straw, which increased the conversion up to 82. 6%. The mechanism analysis showed that PEG could effectively reduce the unproductive adsorption of enzyme on the ASCS. The addition of PEG could increase the soluble protein, filter paper activity (FPA), andβ-glucosidase activity (β-GA) in the supernatant by 15. 0%, 112. 5% and 24. 8%, respectively. The FT-IR analysis showed that the crystal form of ASCS was cellulose Ⅱcrystal structure. The SEM images showed the addition of PEG caused the collapsing of cellulose structure and the residue appeared as irregular bulk.%以玉米秸秆酸爆渣为研究对象,通过物料组成、比表面积和元素组成分析酶解原料的理化特性,研究了聚乙二醇( PEG4000)对玉米秸秆酸爆渣酶解的辅助效果以及作用机理,并利用FT-IR和SEM分析了酸爆玉米秸秆酶解前后的结构变化。结果表明,木质素含量较高的酸爆玉米秸秆具有较大的比表面积,酶解效率较高,在纤维素酶用量15 FPIU/g (以纤维素计,下同)、β-葡萄糖苷酶用量30 U/g,纤维素质量浓度50g/L 条件下水解24 h,葡萄糖得率可达76.4%,PEG4000的添加可以使葡萄糖得率达到82.6%,提高8.1%。对酶解上清液的分析表明,PEG4000改善玉米秸秆酸爆渣酶解性能的作用机制在于其能够有效地与酸爆渣结合,减少酶在酸爆渣上的无效吸附。 PEG4000的添加使上清液中可溶性蛋白、滤纸酶活和β-葡萄糖苷酶活分别上升了15.0%、112.5%和24.8%。 FT-IR和SEM分析显示玉米秸秆酸爆渣为纤维素类物质,晶型以纤维素II型为主,且加入PEG辅助酶解导致纤维结构几乎完全坍塌,残余物表现出无规则的块状结构。
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