National Marine Biodiversity Institute of Korea, Seocheon, 33662, Republic of Korea.
J Microbiol. 2019 May;57(5):372-380. doi: 10.1007/s12275-019-8469-0. Epub 2019 Feb 26.
Chitin is the most abundant biopolymer in marine environments. To facilitate its utilization, our laboratory screened marine-derived fungal strains for chitinolytic activity. One chitinolytic strain isolated from seawater, designated YS2-2, was identified as Acremonium species based on morphological and phylogenetic analyses. Acremonium species are cosmopolitan fungi commonly isolated from both terrestrial and marine environments, but their chitinolytic activity is largely unknown. The extracellular crude enzyme of YS2-2 exhibited optimum chitinolytic activity at pH 6.0-7.6, 23-45°C, and 1.5% (w/v) NaCl. Degenerate PCR revealed the partial cDNA sequence of a putative chitinase gene, chiA, in YS2-2. The expression of chiA was dramatically induced in response to 1% (w/v) colloidal chitin compared to levels under starvation, chitin powder, and glucose conditions. Moreover, the chiA transcript levels were positively correlated with chitinolytic activities under various colloidal chitin concentrations, suggesting that ChiA mediates chitinolytic activity in this strain. Our results provide a basis for additional studies of marinederived chitinolytic fungi aimed at improving industrial applications.
几丁质是海洋环境中最丰富的生物聚合物。为了促进其利用，我们的实验室筛选了具有几丁质酶活性的海洋来源真菌菌株。从海水中分离到的一种具有几丁质酶活性的菌株 YS2-2，根据形态学和系统发育分析被鉴定为枝顶孢属（Acremonium）。枝顶孢属是一种世界性的真菌，通常从陆地和海洋环境中分离出来，但它们的几丁质酶活性在很大程度上是未知的。YS2-2 的胞外粗酶在 pH6.0-7.6、23-45°C 和 1.5%（w/v）NaCl 下表现出最佳的几丁质酶活性。简并 PCR 揭示了 YS2-2 中一个假定的几丁质酶基因 chiA 的部分 cDNA 序列。与饥饿、几丁质粉末和葡萄糖条件下的水平相比，chiA 在 1%（w/v）胶体几丁质的诱导下表达显著增加。此外，chiA 转录水平与各种胶体几丁质浓度下的几丁质酶活性呈正相关，表明 ChiA 介导了该菌株的几丁质酶活性。我们的研究结果为进一步研究海洋来源的几丁质酶真菌以提高工业应用提供了基础。
