产EPA南极细菌的筛选及其脂肪酸成分分析

Screening antarctic bacteria producing EPA and analyzing its composition of fatty acids

目的从南极细菌中筛选高产EPA(二十碳五烯酸)或DHA(二十二碳六烯酸)的细菌,并对其脂肪酸的成分和含量进行分析。方法从南极采集的海冰和土壤中分离得到200株细菌,利用改良的一步反应法,通过气相色谱(GC)初筛,得到8株EPA或DHA产量较高的细菌。对其中一株EPA产量最高菌株(NJ136)的总脂含量采用索氏抽提法测定,各脂肪酸成分和含量采用气相色谱-质谱(GC-MS)分析测定。结果与结论菌株NJ136的EPA相对含量为6.66%,不饱和脂肪酸的相对含量为51.92%,干菌总脂含量是7.94%,EPA含量达到5.3 mg.g-1,不饱和脂肪酸含量达到41.2 mg.g-1。

Objective To screen antarctic bacteria producing EPA and analyse its composition of fatty acids. Methods Two hundred strains of bacteria were isolated from ice and soil of the Antarctic. The total lipid was extracted by using a modified one-phase Bligh and Dyer extraction, and screened by means of GC using fish oil as standard. In the end, eight strains of bacteria were screened which had high content of EPA or DHA. Among them, one bacterium（NJ136） which had the highest content of EPA was obtained, its total lipid was extracted by means of Soxhlet extractor, and the compositions of fatty acids were analysed by means of GC-MS. Results and conclusion The relative contents of EPA and total unsaturated fatty acids of NJ136 were 6.66% and 51.92% respectively, the content of total fat, EPA and unsaturated fatty acids of dry bacteria weight were 7. 94.%,5.3 mg· g^-1 and 41.2 mg· g^-1, respectively.