Biochemical analyses of a novel thermostable GH5 endo β-1,4-mannanase with minor β-1,4-glucosidic cleavage activity from Bacillus sp. KW1 and its synergism with a commercial α-galactosidase on galactomannan hydrolysis
Biochemical analyses of a novel thermostable GH5 endo β-1,4-mannanase with minor β-1,4-glucosidic cleavage activity from Bacillus sp. KW1 and its synergism with a commercial α-galactosidase on galactomannan hydrolysis
复制标题
对来自芽孢杆菌属的一种新型热稳定性 GH5 内切 β-1,4-甘露聚糖酶进行生化分析，该酶具有轻微的 β-1,4-糖苷裂解活性。
DOI：
10.1016/j.ijbiomac.2020.10.235
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发表时间：
2021-01-01
影响因子：
8.2
通讯作者：
Wang, Kui
中科院分区：
文献类型：
--
作者：
Chen, Xi;Wang, Xinhai;Wang, Kui
从芽孢杆菌属中鉴定出一种新型 GH5 内切-1,4-β-甘露聚糖酶 (BaMan5A)。 KW1，它与另一种芽孢杆菌内切 1,4-β-甘露聚糖酶具有最高的序列同一性 (86%)。重组BaMan5A在pH 7.0和70℃下表现出最大活性，在25℃孵育12小时后在较宽的pH范围（pH 3.5-11.0）下稳定，并且表现出良好的热稳定性，在60℃孵育12小时和65℃孵育8小时后分别保留约100％和85％的活性。多糖水解结果表明，该酶只能水解甘露聚糖底物，包括角豆半乳甘露聚糖、魔芋葡甘聚糖、1,4-β-D-甘露聚糖、刺槐豆胶和瓜尔胶，产生甘露糖、甘露二糖、甘露三糖和其他一些低聚糖。最佳底物为角豆半乳甘露聚糖，相应的比活性和Km值分别为10,886 mu mol/min/mu mol和3.31 mg/mL。有趣的是，BaMan5A能够水解甘露寡糖和纤维寡糖，包括甘露四糖、甘露五糖、甘露六糖、纤维五糖和纤维六糖。此外，BaMan5A与市售半乳糖苷酶（CbAgal）对半乳甘露聚糖解聚具有协同作用，优化酶比后达到1.58的最佳协同度。该研究不仅扩大了芽孢杆菌GH5β-甘露聚糖酶的多样性，而且揭示了BaMan5A在工业应用中的潜力。 (c) 2020 Elsevier B.V. 保留所有权利。
A novel GH5 endo-1,4-beta-mannanase (BaMan5A) was identified from Bacillus sp. KW1, it shares the highest sequence identity (86%) with another characterized Bacillus endo-1,4-beta-mannanase. The recombinant BaMan5A displayed maximum activity at pH 7.0 and 70 degrees C, it was stable at a broad pH range (pH 3.5-11.0) after 12-h incubation at 25 degrees C, and exhibited good thermostability, retaining about 100% and 85% activity after incubating at 60 degrees C for 12 h and 65 degrees C for 8 h, respectively. The results of polysaccharide hydrolysis revealed that the enzyme can only hydrolyze mannan substrates, including carob galactomannan, konjac glucomannan, 1,4-beta-D-mannan, locust bean gum, and guar gum, yielding mannose, mannobiose, mannotriose, and some other oligosaccharides. The best substrate was carob galactomannan, the corresponding specific activity and Km value were 10,886 mu mol/min/mu mol and 3.31 mg/mL, respectively. Interestingly, BaMan5A was capable to hydrolyze both manno-oligosaccharides and cello-oligosaccharides, including mannotetraose, mannopentaose, mannohexaose, cellopentaose and cellohexaose. Furthermore, BaMan5A acted synergistically with a commercial agalactosidase (CbAgal) on galactomannan depolymerization, a best synergy degree of 1.58 was achieved after optimizing enzymeratios. This study not only expands the diversity of BacillusGH5 beta-mannanase, but also discloses the potential of BaMan5A in industrial application. (c) 2020 Elsevier B.V. All rights reserved.