产DHA破囊壶菌Aurantiochytrium sp. HX2019010的筛选及其脂肪酸组成分析

为筛选产二十二碳六烯酸(Docosahexaenoic acid,DHA)菌株,从厦门市红树林的海水腐木中分离到一株球状真菌HX2019010,通过扫描电镜观察,测定ITS序列,与Genbank数据库比对,该菌株与破囊壶菌相似性较高。选取ITS序列相似性较高的相近菌株构建的进化树表明,菌株HX2019010与Aurantiochytrium类群聚为一枝,自举检验值较高,初步定名为Aurantiochytrium sp. HX2019010。该菌株在发酵罐中可产生较高浓度的DHA,98 h发酵后生物量达108.27 g/L,总油脂达28.43 g/L,DHA达9.17 g/L。细胞脂肪酸组成分析结果表明,该菌株所产脂肪酸主要为棕榈酸、DHA、肉豆蔻酸等；脂肪酸组成受培养时间或培养条件的影响,总量可达细胞干重的26.26%, 其中DHA占脂肪酸总量的32.25%-45.86%。

Screening of a DHA-producing Aurantochytrium sp. HX2019010 and Analysis of Its Fatty Acid Composition

In order to screen a docosahexaenoic acid (DHA) producing strain, a spherical fungus from the sea rot wood of mangroves in Xiamen City was isolated, which preliminarily identified to be Aurantiochytrium sp. HX2019010, for strain HX2019010 and other Aurantiochytrium strains were clustered together in phylogenetic tree based on ITS sequences from Genbank, and cell morphology observed by scanning electron microscopy is also similar to that of Aurantochytrium. The strain HX2019010 can produce considerable concentration of DHA in the bioreactor. After 98 hours of fermentation, the amount of biomass reaches 108.27 g/L, the total fat reaches 28.43 g/L, and the DHA reaches 9.17 g/L. The fatty acids produced by strain HX2019010 were mainly palmitic acid, DHA, myristic acid, etc., and the composition of fatty acid was affected by the culture time or conditions. The high level of total fat is 26.26% of the dry cell weight, and the proportion of DHA in fatty acids is 32.25%-45.86%.