Han Lijuan, Jiang Baojie, Wang Wei, Wang Gaosheng, Tan Yinshuang, Niu Kangle, Fang Xu
State Key Laboratory of Microbial Technology, Shandong University, Qingdao, Shandong 266237, China.
Rongcheng Huihai Chuangda Biotechnology CO., LTD, Weihai, Shandong 264309, China.
ACS Appl Bio Mater. 2022 May 16;5(5):2253-2261. doi: 10.1021/acsabm.2c00112. Epub 2022 Apr 11.
The nonproductive adsorption of cellulase onto lignin significantly inhibited the enzymatic hydrolysis of lignocellulosic biomass. In this study, we constructed a rapid fluorescence detection (RFD) system, and using this system, we demonstrated that the addition of cationic additives DTAB or polyDADMAC greatly increased the partition coefficients of cellulose/lignin, reduced nonproductive adsorption, and enhanced the hydrolysis efficiency of lignocellulose compared to those of Tweens or PEGs. Moreover, the addition of polyDADMAC and DTAB increased the glucose yield released from the mixture of Avicel and AICS-lignin (MCL) by 16.9 and 20.6%, respectively, and reduced the inhibition rate of lignin by 16.9 and 20.7%, respectively. Interestingly, polyDADMAC or DTAB treatment performed more effectively for the enzymatic hydrolysis of pretreated lignocellulosic biomass, compared with MCL. We confirmed that the reduced hydrophobicity and increased zeta potential of lignin cocontribute to the dampening nonproductive adsorption of lignin. In particular, the zeta potential values of lignin and the partition coefficients of Avicel/lignin with the addition of additives showed a good correlation, suggesting that electrostatic force also plays a crucial role in the adsorbing of cellulase on lignin. This work will be conducive to decreasing the nonproductive binding of cellulase onto lignin and enhancing cellulose conversion.
纤维素酶在木质素上的非生产性吸附显著抑制了木质纤维素生物质的酶水解。在本研究中，我们构建了一种快速荧光检测（RFD）系统，并且利用该系统证明，与吐温或聚乙二醇相比，添加阳离子添加剂十六烷基三甲基溴化铵（DTAB）或聚二烯丙基二甲基氯化铵（polyDADMAC）可大大提高纤维素/木质素的分配系数，减少非生产性吸附，并提高木质纤维素的水解效率。此外，添加polyDADMAC和DTAB分别使从微晶纤维素和碱木质素（MCL）混合物中释放的葡萄糖产率提高了16.9%和20.6%，并分别使木质素的抑制率降低了16.9%和20.7%。有趣的是，与MCL相比，polyDADMAC或DTAB处理对预处理木质纤维素生物质的酶水解更有效。我们证实，木质素疏水性的降低和zeta电位的增加共同导致了木质素非生产性吸附的减弱。特别是，添加添加剂后木质素的zeta电位值与微晶纤维素/木质素的分配系数呈现出良好的相关性，这表明静电力在纤维素酶吸附到木质素上的过程中也起着关键作用。这项工作将有助于减少纤维素酶与木质素的非生产性结合并提高纤维素转化率。
