Angeltveit Camilla F, Jeoh Tina, Horn Svein J
Faculty of Chemistry, Biotechnology, and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway.
Biological and Agricultural Engineering, University of California, Davis, United States.
Bioresour Technol. 2023 Dec;389:129806. doi: 10.1016/j.biortech.2023.129806. Epub 2023 Sep 27.
Cellobiohydrolases are crucial for cellulose breakdown, but their efficiency on crystalline cellulose is hampered by limited access to single chain ends to initiate hydrolysis. As a result, they depend on enzymes like lytic polysaccharide monooxygenases (LPMOs), which directly target the crystalline cellulose surface. This study investigated how LPMO pretreatment affected the productive binding capacity of a Trichoderma longibrachiatum cellobiohydrolase, TlCBHI, on crystalline cellulose by applying an amperometric cellobiose dehydrogenase biosensor. After the 24-hour of LPMO pretreatment, the productive binding capacity of TlCBHI significantly increased in all reactions. However, with a shorter 5-hour LPMO pretreatment, minimal to no effect on productive binding capacity was observed. Of note, all LPMO reactions were inactivated around this time point. This delayed LPMO effect suggests that the improved binding capacity for cellulases does not directly result from cellulose chain cleavage by LPMOs but rather from the cellulose decrystallization following the oxidative cleavage.
纤维二糖水解酶对于纤维素的分解至关重要，但其对结晶纤维素的效率受到单链末端用于启动水解的可及性有限的阻碍。因此，它们依赖于诸如裂解多糖单加氧酶（LPMOs）之类的酶，这些酶直接作用于结晶纤维素表面。本研究通过应用安培型纤维二糖脱氢酶生物传感器，研究了LPMO预处理如何影响长枝木霉纤维二糖水解酶TlCBHI对结晶纤维素的有效结合能力。经过24小时的LPMO预处理后，在所有反应中TlCBHI的有效结合能力均显著增加。然而，LPMO预处理时间缩短至5小时时，对有效结合能力的影响极小或未观察到影响。值得注意的是，所有LPMO反应在这个时间点左右均失活。这种LPMO效应延迟表明，纤维素酶结合能力的提高并非直接源于LPMOs对纤维素链的切割，而是源于氧化切割后纤维素的去结晶化。
