In this study, two novel thermostable lytic polysaccharide monooxygenases (LPMOs) were cloned from thermophilic fungus Scytalidium thermophilum (PMO9D_SCYTH) and Malbranchea cinnamomea (PMO9D_MALCI) and expressed in the methylotrophic yeast Pichia pastoris X33. The purified PMO9D_SCYTH was active at 60 °C (t_1/2 = 60.58 h, pH 7.0), whereas, PMO9D_MALCI was optimally active at 50 °C (t_1/2 = 144 h, pH 7.0). The respective catalytic efficiency (k_cat/K_m) of PMO9D_SCYTH and PMO9D_MALCI determined against avicel in presence of H₂O₂ was (6.58 × 10^-3 and 1.79 × 10^-3 mg^-1 ml min^-1) and carboxy-methylcellulose (CMC) (1.52 × 10^-1 and 2.62 × 10^-2 mg^-1 ml min^-1). The HRMS analysis of products obtained after hydrolysis of avicel and CMC showed the presence of both C₁ and C₄ oxidized oligosaccharides, in addition to phylogenetic tree constructed with other characterized type 1 and 3 LPMOs demonstrated that both LPMOs belongs to type-3 family of AA9s. The release of sugars during saccharification of acid/alkali pretreated sugarcane bagasse and rice straw was enhanced upon replacing one part of commercial enzyme Cellic CTec2 with these LPMOs.

中文翻译：

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从嗜热真菌中发现并表达热稳定的LPMO，以生产高效的木质纤维素分解酶鸡尾酒。

在这项研究中，从嗜热真菌Scytalidium thermophilum（PMO9D_SCYTH）和Malbranchea cinnamomea（PMO9D_MALCI）中克隆了两种新型的热稳定性裂解多糖单加氧酶（LPMO），并在甲基营养酵母巴斯德毕赤酵母X33中表达。纯化的PMO9D_SCYTH在60°C（t _1/2 = 60.58 h，pH 7.0）下具有活性，而PMO9D_MALCI在50°C（t _1/2 = 144 h，pH 7.0）上具有最佳活性。在H ₂ O ₂存在下，PMO9D_SCYTH和PMO9D_MALCI对avicel的催化效率（k _cat / K _m）为（6.58×10 ^-3和1.79×10^-3 mg ^-1 ml min ^-1）和羧甲基纤维素（CMC）（1.52×10 ^-1和2.62×10 ^-2 mg ^-1 ml min ^-1）。avicel和CMC水解后获得的产物的HRMS分析表明，除了用其他特征性1型和3型LPMO构建的系统树以外，C ₁和C ₄氧化寡糖均存在，这表明这两个LPMO均属于CLP的3型家族。 AA9s。用这些LPMO代替商业酶Cellic CTec2的一部分，可以增强酸/碱预处理的甘蔗渣和稻草糖化过程中糖的释放。