亚硫酸盐预处理对蔗渣酶解效率的影响

为了破坏蔗渣的抗降解性,获得高的酶解效率,采用亚硫酸盐法对蔗渣进行预处理,探讨亚硫酸氢钠用量对蔗渣理化性质、表面磺酸基含量(磺化度)及酶解效率的影响,并进一步分析了磺化度对酶解效率的影响。结果显示:不同亚硫酸氢钠用量蔗渣的结晶度(I_(Cr))变化不显著,但预处理后蔗渣纤维素结晶区相对含量上升,半纤维素含量减少。50 g蔗渣,按固液比1∶8(g∶m L)加入1.1%的稀硫酸,亚硫酸氢钠加入量(以绝干蔗渣计)为8%,在160℃条件下反应30 min时制得的蔗渣其表面磺酸基最多,达131.73μmol/g。在2%干蔗渣,7.5 FPU/g(以干蔗渣计),50℃,72 h酶解条件下,对不同磺化度的蔗渣进行酶解,结果显示酶解效率随底物的磺化度升高而升高,最高综纤维素水解效率可达83.76%。研究表明:蔗渣的酶解效率与磺酸基团的含量呈正相关,而与蔗渣中纤维素的结晶度关系不明显;酸性亚硫酸盐法可除去绝大部分半纤维素,破坏蔗渣抗降解性,促进酶解效率。

Effect of Sulfite Pretreatment on Hydrolysis Efficiency ofSugarcane Bagasse

To overcome the anti-degradation of sugarcane bagasse, sulfite pretreatment (SPORL) was used and the effects of sodium bisulfite concentration on the physicochemical characteristics, the sulfonic acid group on the surface(sulfonation degree) and hydrolysis efficiency of sugarcane bagasse were investigated, and the effect of sulfonation degree on hydrolysis efficiency of bagasse was further studied.The results revealed that different sodium bisulfite concentration had no significant influences on the crystrallinity index (ICr) of bagasse and bagasse samples treated by SPORL had more crystalline cellulose and less hemicellulose.Besides, 50 g oven bagasse with 1∶8 solid-liquid ratio was treated by adding 8% sodium bisulfite(based on the dry bagasse) at 160 ℃ for 30 min and 131.73 μmol/g sulfonic group was obtained.The hydrolyses of bagasse with different degree of sulfonation were conducted at 50 ℃ for 72 h as 7.5 FPU/g dry bagasse (based on 2% dry bagasse).The results demonstrated that the enzymatic efficiency increased with the increase of degree of sulfonation and the highest hydrolysis efficiency of holocellulose was 83.76%.The study indicated that the hydrolysis efficiency of bagasse was positively related to sulfonic group content in bagasse and had no significant relationship with crystallinity degree of bagasse.Low-pH SPORL could remove most hemicellulose in bagasse, and the anti-degradation of bagasse was overcome.Finally, the enzymatic hydrolysis of lignocellulose was enhanced as well.