Culturable diversity and biochemical features of thraustochytrids from coastal waters of Southern China
Culturable diversity and biochemical features of thraustochytrids from coastal waters of Southern China
复制标题
华南沿海破囊壶菌的可培养多样性及生化特征
DOI：
10.1007/s00253-013-5391-y
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发表时间：
2014-04-01
影响因子：
5
通讯作者：
Wang, Guangyi
中科院分区：
文献类型：
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作者：
Liu, Ying;Singh, Purnima;Wang, Guangyi
破囊壶菌是一种广泛存在的海洋异养真菌类微生物，目前已鉴定的种类仅40余种。本研究共从沿海生境中分离到60株破囊壶菌。18 S rRNA基因序列分析表明，它们分属于三个属，裂殖壶菌属、橙黄壶菌属和破囊壶菌属。所有的菌株被发现显示出相当大的纤维素分解和脂肪分解活动。发现橙黄壶菌属和破囊壶菌属的菌株产生最高水平的胞外多糖（EPS），其在生长培养基中达到345 μ g/ml。来自两种破囊壶菌（PKU#Sed1和#SW1）的EPS样品的傅里叶变换红外（FTIR）光谱显示碳水化合物、蛋白质、脂质、糖醛酸和核酸的峰。四种破囊壶菌的脂肪酸组成主要为棕榈酸（C16：0）和二十二碳六烯酸（DHA）。Schizochytrium sp.在生长的第四天表现出最高的DHA产量，占总脂肪酸（TFA）的44%，生物量和DHA产量分别为7.1和1.6 g l（-1）。所有四个分离株在其脂肪酸谱中表现出相当大的棕榈酸产量（16：0），范围为35至50%TFA。这是首次报道从中国沿海生境中分离的破囊壶菌胞外酶、EPS和DHA的产生。
Thraustochytrids are ubiquitous marine osmo-heterotrophic fungi-like microorganisms with only about 40 identified species till now. In this study, a total of 60 thraustochytrid strains were isolated from marine coastal habitats. Analysis of 18S rRNA gene sequences revealed that they belonged to three genera, i.e., Schizochytrium, Aurantiochytrium, and Thraustochytrium. All of the isolates were found to show considerable cellulolytic and lipolytic activities. Strains of Aurantiochytrium sp. and Thraustochytrium sp. were found to produce the highest levels of extracellular polysaccharides (EPS), which reached 345 mu g ml(-1) in the growth media. Fourier transform infrared (FTIR) spectra of the EPS samples derived from two thraustochytrids (PKU#Sed1 and #SW1) displayed peaks for carbohydrates, proteins, lipids, uronic acids, and nucleic acids. Fatty acid profiles of four thraustochytrids comprised of palmitic acid (C16:0) and docosahexaenoic acid (DHA) as their major constituents. Schizochytrium sp. demonstrated the highest DHA production at 44 % of total fatty acids (TFA) with biomass and DHA yield of 7.1 and 1.6 g l(-1), respectively, on the fourth day of growth. All the four isolates exhibited considerable production of palmitic acid (16:0) in their fatty acid profiles ranging from 35 to 50 % TFA. This is the first report on extracellular enzymes, EPS, and DHA production from thraustochytrids isolated from the coastal habitats of China.