Endo-xylanases from Cohnella sp. AR92 aimed at xylan and arabinoxylan conversion into value-added products,Applied Microbiology and Biotechnology

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Endo-xylanases from Cohnella sp. AR92 aimed at xylan and arabinoxylan conversion into value-added products
Applied Microbiology and Biotechnology ( IF 3.9 ) Pub Date : 2021-08-30 , DOI: 10.1007/s00253-021-11495-5
Johan S Hero ₁ , José H Pisa ₁ , Cintia M Romero _{1,

2} , Eva Nordberg Karlsson ₃ , Javier A Linares-Pastén ₃ , M Alejandra Martinez _{1,

4}

Affiliation

The genus Cohnella belongs to a group of Gram-positive endospore-forming bacteria within the Paenibacillaceae family. Although most species were described as xylanolytic bacteria, the literature still lacks some key information regarding their repertoire of xylan-degrading enzymes. The whole genome sequence of an isolated xylan-degrading bacterium Cohnella sp. strain AR92 was found to contain five genes encoding putative endo-1,4-β-xylanases, of which four were cloned, expressed, and characterized to better understand the contribution of the individual endo-xylanases to the overall xylanolytic properties of strain AR92. Three of the enzymes, CoXyn10A, CoXyn10C, and CoXyn11A, were shown to be effective at hydrolyzing xylans-derived from agro-industrial, producing oligosaccharides with substrate conversion values of 32.5%, 24.7%, and 10.6%, respectively, using sugarcane bagasse glucuronoarabinoxylan and of 29.9%, 19.1%, and 8.0%, respectively, using wheat bran-derived arabinoxylan. The main reaction products from GH10 enzymes were xylobiose and xylotriose, whereas CoXyn11A produced mostly xylooligosaccharides (XOS) with 2 to 5 units of xylose, often substituted, resulting in potentially prebiotic arabinoxylooligosaccharides (AXOS). The endo-xylanases assay displayed operational features (temperature optima from 49.9 to 50.4 °C and pH optima from 6.01 to 6.31) fitting simultaneous xylan utilization. Homology modeling confirmed the typical folds of the GH10 and GH11 enzymes, substrate docking studies allowed the prediction of subsites (− 2 to + 1 in GH10 and − 3 to + 1 in GH11) and identification of residues involved in ligand interactions, supporting the experimental data. Overall, the Cohnella sp. AR92 endo-xylanases presented significant potential for enzymatic conversion of agro-industrial by-products into high-value products.

Key points

• Cohnella sp. AR92 genome encoded five potential endo-xylanases.

• Cohnella sp. AR92 enzymes produced xylooligosaccharides from xylan, with high yields.

• GH10 enzymes from Cohnella sp. AR92 are responsible for the production of X2 and X3 oligosaccharides.

• GH11 from Cohnella sp. AR92 contributes to the overall xylan degradation by producing substituted oligosaccharides.

Graphical abstract

中文翻译：

来自 Cohnella sp. 的内切木聚糖酶。AR92旨在将木聚糖和阿拉伯木聚糖转化为增值产品

属Cohnella所属的组的Paenibacillaceae家庭内的革兰氏阳性形成内生孢子的细菌。尽管大多数物种被描述为木聚糖分解细菌，但文献仍然缺乏关于它们的木聚糖降解酶库的一些关键信息。分离的木聚糖降解细菌Cohnella sp.的全基因组序列。发现菌株 AR92 含有五个编码假定内切-1,4- β 的基因-木聚糖酶，其中四种被克隆、表达和表征，以更好地了解各个内切木聚糖酶对 AR92 菌株的整体木聚糖分解特性的贡献。三种酶 CoXyn10A、CoXyn10C 和 CoXyn11A 被证明可有效水解来自农业工业的木聚糖，使用甘蔗渣葡糖醛酸阿拉伯糖生产底物转化率分别为 32.5%、24.7% 和 10.6% 的低聚糖和 29.9%、19.1% 和 8.0%，分别使用麦麸衍生的阿拉伯木聚糖。GH10 酶的主要反应产物是木二糖和木三糖，而 CoXyn11A 主要产生木寡糖 (XOS)，其中含有 2 到 5 个单位的木糖，通常被取代，从而产生潜在的益生元阿拉伯木寡糖 (AXOS)。内切木聚糖酶分析显示操作特征（最佳温度为 49.9 至 50.4 °C，最佳 pH 值为 6.01 至 6.31），适合同时使用木聚糖。同源性建模证实了 GH10 和 GH11 酶的典型折叠，底物对接研究允许预测亚位点（GH10 中的 - 2 至 + 1 和 GH11 中的 - 3 至 + 1）并鉴定参与配体相互作用的残基，支持实验数据。总体而言，支持实验数据。总体而言，支持实验数据。总体而言，Cohnella sp. AR92 内切木聚糖酶具有将农业工业副产品酶促转化为高价值产品的巨大潜力。

关键点

• Cohnella sp。AR92 基因组编码五种潜在的内切木聚糖酶。

• Cohnella sp。AR92 酶从木聚糖中以高产率生产低聚木糖。

•来自 Cohnella sp. 的 GH10 酶。AR92 负责生产 X2 和 X3 寡糖。

•来自 Cohnella sp. 的 GH11。AR92 通过产生取代的寡糖促进整体木聚糖降解。