Comparison of different lignin removal processes for corn stover on cellulase adsorption and enzymatic hydrolysis

doi:10.11949/j.issn.0438-1157.20151570

Abstract

Abstract:

Experiments were conducted for various pretreated substrates to investigate the impact of lignin content on cellulase adsorption and substrate digestibility. Compared with other treatments, 2% (mass) NaOH pretreated solids with the highest level of lignin removal (85%) exhibited the highest accessibility to cellulase [4.7 mg protein·(g glucan)^-1] and enzymatic digestibility (18.9%). The obtained maximum adsorption capacity (W_max) and equilibrium constant (K) derived from fitting the Langmuir adsorption isotherm for different delignified substrates indicated that the removal of lignin benefited cellulase adsorption. The relationship between cellulase adsorption capacities and enzymatic digestibility for raw and pretreated solids correlated well (R²>0.8), supporting the hypothesis that carbohydrate conversion was primarily dominated by enhancing substrate accessibility owing to lignin removal. Nevertheless, further delignification by NaOH with concentrations of 3% (mass) and 4% (mass) was unfavorable to improving substrate accessibility to cellulase and enhancing carbohydrates conversion to monosaccharide. It appeared that the appropriate delignification to some degree was a significant pretreatment factor to be taken into consideration to achieve more effectively enzymatic digestibility.

Key words: corn stover, biomass, bioenergy, cellulase adsorption, pretreatment, lignin removal, enzymatic digestibility

摘要：

利用不同预处理方法获得的玉米秸秆底物研究木质素脱除对纤维素酶吸附量及酶解效率的影响。相比于其他处理方法,2%(质量分数)NaOH处理的底物具有最高的木质素脱除率(85%),最高的底物可及性[4.7 mg·(g 葡聚糖)^-1]及酶解效率(18.9%)。通过对不同处理获得的底物进行Langmuir吸附等温曲线模拟,获得了最大吸附量(W_max)与吸附平衡常数(K),且木质纤维素酶水解效率与纤维素酶吸附量具有很好的线性关系(R²>0.8),表明脱除木质素能很好地提高底物可及性与酶解效率。然而,提高NaOH浓度(3%,4%)进一步脱除木质素时,底物可及性与碳水化合物转化为单糖的效率反而明显下降。因此,适当脱除木质素而提高底物对纤维素酶的可及性将有助于获得更有效的酶水解效果。

关键词: 玉米秸秆, 生物质, 生物能源, 纤维素酶吸附, 预处理, 木质素脱除, 酶水解效率

CLC Number:

TS721.1

TIAN Shunfeng, CHENG Li, GU Zhengbiao, HONG Yan, LI Zhaofeng, LI Caiming. Comparison of different lignin removal processes for corn stover on cellulase adsorption and enzymatic hydrolysis[J]. CIESC Journal, 2016, 67(5): 2084-2092.

田顺风, 程力, 顾正彪, 洪雁, 李兆丰, 李才明. 玉米秸秆中不同木质素脱除方法对纤维素酶吸附及酶解效果的比较[J]. 化工学报, 2016, 67(5): 2084-2092.

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