酸性低共熔溶剂预处理对木质纤维素的分馏具有很大的前景。很少研究木质素存在形式和预处理残渣表面结构对酶解的影响。在目前的工作中,开发了氯化胆碱/草酸(ChCl/OA)来预处理毛竹以促进其酶促水解,并探讨了残基变化对酶促水解的影响。结果表明,在温和条件下(90°C 3 小时)ChCl/OA 预处理后,半纤维素 (76.24%) 和木质素 (60.68%) 的去除效果显着。酶水解后,葡萄糖产率从 17.78%(原始)提高到 60.39%(在 90 °C 下预处理 3 小时获得的残留物)。然而,过度去除木质素 (73. 43%) 不促进在 100°C 下从 ChCl/OA 预处理 3 小时获得的残留物的酶促水解。ChCl/OA预处理残渣的表面形貌、表面理化和染料吸附结果证实,酶促水解受表面木质素、疏水相互作用和可及性的影响,其中导致酶非生产性吸附的疏水性可能是导致葡萄糖产量下降的主导因素。最后,在酶解过程中加入牛血清蛋白可以有效克服酶的非生产性吸附,110 ℃ 3 h 预处理得到的残渣的葡萄糖收率可以提高到 2.3 倍。ChCl/OA预处理残渣的吸附和染料吸附证实酶促水解受表面木质素、疏水相互作用和可及性的影响,其中导致酶非生产性吸附的疏水性可能是导致葡萄糖产量降低的主导因素. 最后,在酶解过程中加入牛血清蛋白可以有效克服酶的非生产性吸附,110 ℃ 3 h 预处理得到的残渣的葡萄糖收率可以提高到 2.3 倍。ChCl/OA预处理残渣的吸附和染料吸附证实酶促水解受表面木质素、疏水相互作用和可及性的影响,其中导致酶非生产性吸附的疏水性可能是导致葡萄糖产量降低的主导因素. 最后,在酶解过程中加入牛血清蛋白可以有效克服酶的非生产性吸附,110 ℃ 3 h 预处理得到的残渣的葡萄糖收率可以提高到 2.3 倍。其中导致酶非生产性吸附的疏水性可能是导致葡萄糖产率下降的主导因素。最后,在酶解过程中加入牛血清蛋白可以有效克服酶的非生产性吸附,110 ℃ 3 h 预处理得到的残渣的葡萄糖收率可以提高到 2.3 倍。其中导致酶非生产性吸附的疏水性可能是导致葡萄糖产率下降的主导因素。最后,在酶解过程中加入牛血清蛋白可以有效克服酶的非生产性吸附,110 ℃ 3 h 预处理得到的残渣的葡萄糖收率可以提高到 2.3 倍。
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Acidic deep eutectic solvent pretreatment for enhancing enzymatic hydrolysis of moso bamboo (Phyllostachys pubescens)
Acidic deep eutectic solvent pretreatment holds great promise for the fractionation of lignocellulose. The influences of lignin presence form and surface structure of pretreated residue on enzymatic hydrolysis are rarely studied. In the present work, choline chloride/oxalic acid (ChCl/OA) was developed to pretreat moso bamboo for promoting its enzymatic hydrolysis, and the effects of residue changes on enzymatic hydrolysis were also explored. Results showed that the removal of hemicelluloses (76.24%) and lignin (60.68%) was remarkable after ChCl/OA pretreatment at mild conditions (at 90 °C for 3 h). After enzymatic hydrolysis, the glucose yield was improved from 17.78% (raw) to 60.39% (the residue obtained from pretreatment at 90 °C for 3 h). However, the excessive removal of lignin (73.43%) did not facilitate the enzymatic hydrolysis of residue obtained from ChCl/OA pretreatment at 100°C for 3 h. The results of surface morphology, surface physiochemistry, and dye adsorption of ChCl/OA pretreatment residues confirmed that the enzymatic hydrolysis was affected by the surface lignin, hydrophobic interaction, and accessibility, among which the hydrophobicity causing the enzyme non-productive adsorption may be the dominant factor leading to the decrease of glucose yield. Finally, the enzyme non-productive adsorption could be effectively overcome by adding bovine serum protein during enzymatic hydrolysis, and its glucose yield could be improved to 2.3-fold for the residue obtained from pretreatment at 110 °C for 3 h.