Efficient enzymatic saccharification of lignocellulosic substrates requires a blend of different hydrolytic and oxidative enzymes: cellulases, β-glucosidases, and lytic polysaccharide monooxygenases (LPMOs). In aerobic systems, reactions between lignin and oxygen will generate the LPMO cosubstrate H₂O₂. This in situ generation of H₂O₂ is essential to keep LPMOs active during saccharification processes but is challenging to control, particularly in the presence of transition metals. In this study, H₂O₂ generation and LPMO activity during saccharification reactions with LPMO-containing cellulolytic enzyme cocktails were manipulated using light of different wavelengths and lignin at different concentrations. The results show that light and its wavelength greatly impact H₂O₂ production resulting from abiotic oxidation of lignin, with major effects on LPMO activity, the stability of both the LPMOs and the cellulases, and saccharification efficiency. Light may have a negative effect on the overall efficiency of cellulolytic enzyme cocktails acting on lignin-containing cellulosic material, because light can induce excessive production of H₂O₂. Importantly, our data suggest that the LPMOs contribute not only by cleaving cellulose but also by removing excess H₂O₂ that otherwise could harm the cellulases.

中文翻译：

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木质素的光照影响含 LPMO 的纤维素分解酶混合物的糖化效率


木质纤维素底物的高效酶促糖化需要混合不同的水解酶和氧化酶：纤维素酶、β-葡萄糖苷酶和裂解多糖单加氧酶 (LPMO)。在有氧系统中，木质素和氧气之间的反应将生成LPMO共底物H ₂ O ₂ 。 H ₂ O ₂ 的原位生成对于糖化过程中保持 LPMO 活性至关重要，但控制起来具有挑战性，特别是在存在过渡金属的情况下。在这项研究中，使用不同波长的光和不同浓度的木质素来控制含LPMO的纤维素分解酶混合物的糖化反应过程中H ₂ O ₂ 的产生和LPMO活性。结果表明，光及其波长极大地影响木质素非生物氧化产生的 H ₂ O ₂ 的产生，对 LPMO 活性、LPMO 和纤维素酶的稳定性有重大影响和糖化效率。光可能对作用于含木质素纤维素材料的纤维素分解酶混合物的总体效率具有负面影响，因为光可诱导H ₂ O ₂ 的过量产生。重要的是，我们的数据表明，LPMO 不仅可以裂解纤维素，还可以去除过量的 H ₂ O ₂ ，否则可能会损害纤维素酶。