Photobiocatalysis Unit - CPBL, and Biomass Transformation Lab - BTL, École Interfacultaire de Bioingénieurs, Université Libre de Bruxelles, Belgium.
4Mat, Ecole Polytechnique de Bruxelles, Université Libre de Bruxelles, Belgium.
Bioresour Technol. 2022 Mar;347:126375. doi: 10.1016/j.biortech.2021.126375. Epub 2021 Nov 18.
Lytic Polysaccharide MonoOxygenases display great variability towards cellulose ultrastructure while performing oxidative functionalization of the polymers. Aiming at employing AA9-LPMOs for isolation of cellulose nano-crystals (CNCs), the ratio between functionalization/crystalline degradation became a crucial parameter. Here are reported the constraints posed by the substrate ultrastructure on the activity of seven different AA9 LPMOs representative of various regioselectivity and substrate affinity: TtAA9E, TaAA9A, PcAA9D, MtAA9A, MtAA9D, MtAA9I-CBM and MtAA9J. The substrate crystallinity and dry matter loading greatly affected the seven AA9s in an enzyme-specific manner, impacting their efficiency for CNCs functionalization purposes. X-ray diffraction pattern analyses were used to assess the cracking efficacy of the enzymatic treatment to de-crystallize CNCs, revealing that those AA9s with minor efficiency in releasing oligosaccharides resulted instead the most disruptive towards the crystal lattice and in reducing the particle sizes. These non-catalytic effects were found comparable with the one caused by the expansin BsEXLX1 enzyme.
溶细胞单加氧酶在对聚合物进行氧化功能化时，对纤维素超微结构表现出很大的可变性。为了将 AA9-LPMO 用于分离纤维素纳米晶体（CNC），功能化/结晶降解的比例成为一个关键参数。本研究报告了七种不同 AA9 LPMO 的活性受到不同区域选择性和底物亲和力的代表性限制：TtAA9E、TaAA9A、PcAA9D、MtAA9A、MtAA9D、MtAA9I-CBM 和 MtAA9J。底物结晶度和干物质加载量以酶特异性的方式极大地影响了这七种 AA9，影响了它们用于 CNC 功能化的效率。X 射线衍射图谱分析用于评估酶处理对去结晶 CNC 的开裂效果，结果表明，那些在释放低聚糖方面效率较低的 AA9 反而对晶格的破坏作用最大，导致颗粒尺寸减小。这些非催化作用与扩展蛋白 BsEXLX1 酶引起的作用相当。
