Department of Biology, University of Naples Federico II, 80126 Naples, Italy.
Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
Int J Mol Sci. 2022 Dec 23;24(1):243. doi: 10.3390/ijms24010243.
In the bio-based era, cellulolytic and hemicellulolytic enzymes are biocatalysts used in many industrial processes, playing a key role in the conversion of recalcitrant lignocellulosic waste biomasses. In this context, many thermophilic microorganisms are considered as convenient sources of carbohydrate-active enzymes (CAZymes). In this work, a functional genomic annotation of FL18, a recently discovered thermo-acidophilic microorganism, showed a wide reservoir of putative CAZymes. Among them, a novel enzyme belonging to the family 9 of glycosyl hydrolases (GHs), named AmCel9, was identified; in-depth in silico analyses highlighted that AmCel9 shares general features with other GH9 members. The synthetic gene was expressed in and the recombinant protein was purified and characterized. The monomeric enzyme has an optimal catalytic activity at pH 6.0 and has comparable activity at temperatures ranging from 40 °C to 70 °C. It also has a broad substrate specificity, a typical behavior of multifunctional cellulases; the best activity is displayed on β-1,4 linked glucans. Very interestingly, AmCel9 also hydrolyses filter paper and microcrystalline cellulose. This work gives new insights into the properties of a new thermophilic multifunctional GH9 enzyme, that looks a promising biocatalyst for the deconstruction of lignocellulose.
在生物基时代，纤维素酶和半纤维素酶等生物催化剂被广泛应用于许多工业过程中，在转化木质纤维素等难处理生物质方面发挥着关键作用。在此背景下，许多嗜热微生物被认为是碳水化合物活性酶（CAZymes）的便利来源。在这项工作中，对最近发现的嗜热嗜酸微生物 FL18 进行了功能基因组注释，结果显示其拥有广泛的潜在 CAZymes 储备。其中，鉴定到一种属于糖苷水解酶（GHs）家族 9 的新型酶，命名为 AmCel9；深入的计算机分析表明，AmCel9 与其他 GH9 成员具有共同的特征。合成基因在 中进行表达，随后对重组蛋白进行了纯化和特性分析。该单体酶在 pH6.0 时具有最佳的催化活性，在 40°C 到 70°C 的温度范围内具有相当的活性。它还具有广泛的底物特异性，这是多功能纤维素酶的典型特征；在β-1,4 连接的葡聚糖上显示出最佳的活性。非常有趣的是，AmCel9 还能水解滤纸和微晶纤维素。这项工作深入了解了一种新型嗜热多功能 GH9 酶的特性，该酶有望成为木质纤维素解构的理想生物催化剂。
