State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou, China.
J Agric Food Chem. 2010 Jun 23;58(12):7233-8. doi: 10.1021/jf1001588.
This study investigated the inhibition of enzymatic hydrolysis by unbound lignin (soluble and insoluble) with or without the addition of metal compounds. Sulfonated, Organosolv, and Kraft lignin were added in aqueous enzyme-cellulose systems at different concentrations before hydrolysis. The measured substrate enzymatic digestibility (SED) of cellulose was decreased by 15% when SL was added to a concentration of 0.1 g/L due to nonproductive adsorption of enzymes onto lignin. Cu(II) and Fe(III) were found to inhibit enzymatic cellulose hydrolysis in the presence of lignin. Ca(II) and Mg(II) were found to reduce or eliminate nonproductive enzyme adsorption by the formation of lignin-metal complex. The addition of Ca(II) or Mg(II) to a concentration of 10 mM can almost completely eliminate the reduction in SED caused by the nonproductive enzyme adsorption onto the lignins studied (SL, OL, or KL at concentration of 0.1 g/L). Ca(II) was also found to reduce the inhibitive effect of bound lignin in pretreated wood substrate, suggesting that Ca(II) can also form complex with bound lignin on pretreated solid lignocelluloses. Significant improvement in SED of about over 27% of a eucalyptus substrate produced by sulfite pretreatment to overcome recalcitrance of lignocellulose (SPORL) was achieved with the application of Ca(II).
本研究考察了未结合木质素（可溶和不可溶）在添加或不添加金属化合物的情况下对酶解的抑制作用。在水解前，将磺化木质素、有机溶剂木质素和 Kraft 木质素以不同浓度添加到含水酶-纤维素体系中。当 SL 添加到 0.1g/L 的浓度时，由于酶对木质素的非生产性吸附，纤维素的测量酶解底物消化率（SED）降低了 15%。发现 Cu(II)和 Fe(III)在木质素存在下抑制酶解纤维素水解。发现 Ca(II)和 Mg(II)通过形成木质素-金属配合物来减少或消除非生产性酶对木质素的吸附。将 Ca(II)或 Mg(II)添加到 10mM 的浓度可以几乎完全消除非生产性酶吸附到研究的木质素（SL、OL 或 KL，浓度为 0.1g/L）上导致的 SED 降低。还发现 Ca(II)可以降低预处理木材底物中结合木质素的抑制作用，这表明 Ca(II)也可以与预处理固体木质纤维素上的结合木质素形成配合物。通过应用 Ca(II)，对亚硫酸盐预处理克服木质纤维素的顽固性（SPORL）产生的桉木底物的 SED 提高了约 27%以上。
