Chitinases play an important role in many industrial processes, including the preparation of oligosaccharides with potential applications. In the present study, a 1,713 bp gene of Chi1602, derived from a marine bacterium Microbulbifer sp. BN3, encoding a GH18 family chitinase, was expressed at high levels in Pichia pastoris. Distinct from most of the marine chitinases, the recombinant chitinase 1602 exhibited maximal activity at 60 °C and over a broad pH range between 5.0 and 9.0, and was stable at 50 °C and over the pH range 4.0–9.0. The hydrolytic products derived from colloidal chitins comprised mainly (GlcNAc)₂ and GlcNAc, indicating that rChi1602 is a GH18 processive chitinase in conformity with its hypothetical structure. However, rChi1602 showed traces of β-N-acetylglucosaminidase activity on substrates such as powder chitin, chitosan, and ethylene glycol chitin. The thermophilic rChi1602, which manifests adaptation to a wide pH range and can be expressed at a high level in P. pastoris, is advantageous for applications in industrial processes.

中文翻译：

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来自海洋细菌 Microbulbifer sp. 的嗜热几丁质酶 1602。BN3 及其在毕赤酵母中的高水平表达

几丁质酶在许多工业过程中发挥着重要作用，包括具有潜在应用的低聚糖的制备。在本研究中，来自海洋细菌Microbulbifer sp.的Chi1602的 1,713 bp 基因。BN3 编码 GH18 家族几丁质酶，在毕赤酵母中高水平表达。与大多数海洋几丁质酶不同，重组几丁质酶 1602 在 60 °C 和 5.0 至 9.0 的宽 pH 范围内表现出最大活性，并在 50 °C 和 4.0-9.0 的 pH 范围内稳定。胶体几丁质的水解产物主要包括 (GlcNAc) ₂和 GlcNAc，表明 rChi1602 是与其假设结构一致的 GH18 持续性几丁质酶。然而，rChi1602 在底物如粉状几丁质、壳聚糖和乙二醇几丁质上显示出微量的 β-N-乙酰氨基葡萄糖苷酶活性。嗜热 rChi1602 表现出对广泛 pH 范围的适应性，并且可以在毕赤酵母中高水平表达，有利于工业过程中的应用。