三元DES预处理杨木屑促进纤维素酶水解的研究

Study on Ternary DES Pretreated Poplar Sawdust for Boosting Enzymatic Hydrolysis of Cellulose

中文关键词:  DES  预处理  酶水解  结晶度  结晶指数

Key Words:deep eutectic solvent  pretreatment  enzymatic hydrolysis  crystallinity  crystallization index

中文摘要:

      采用由对甲基苯磺酸、氯化胆碱和乙醇组成的新型三元低共熔溶剂（DES）对杨木屑进行预处理，研究了三元DES预处理对杨木屑木质纤维化学组分、微观形态、结晶结构、化学结构及纤维素酶水解效果的影响。结果表明，和杨木屑原料相比，二元DES预处理物料的木质素脱除率不升反降，而添加乙醇的三元DES预处理物料的木质素脱除率提高至69.2%；三元DES体系可有效抑制物料表面酸不溶物质的形成，减少纤维素酶的无效吸附，可将纤维素酶水解效率提高至76.6%；在三元DES预处理过程中，半纤维素、木质素以及纤维素无定形区结构的破坏导致纤维素结晶度由原料的48.7%提高至65.7%，纤维素结晶指数由0.66提高至0.76。

Abstract:

      A novel ternary deep eutectic solvent （DES） consisting of p-toluenesulfonic acid， choline chloride， and ethanol was used to pretreat poplar sawdust. The changes in chemical component， microscopic morphology， crystalline and chemical structure of poplar sawdust fiber during the ternary DES pretreatment process were investigated， as well as the effect of ternary DES pretreatment on the cellulose enzymatic hydrolysis. The results showed that the lignin removal rate of binary DES pretreated residues decreased rather than increased compared with that of raw poplar sawdust， while the lignin removal rate of ternary DES pretreated residues increased to 69.2%. The ternary DES system effectively inhibited the formation of acid-insoluble component on the surface of the residues， reduced invalid adsorption of cellulase， and significantly increased the efficiency of enzymatic hydrolysis to 76.6%. The destruction of hemicellulose， lignin， and amorphous cellulose during the ternary DES pretreatment resulted in the increase of crystallinity and crystallization index from 48.7% （poplar sawdust） to 65.7% and 0.66 （poplar sawdust） to 0.76， respectively.