从几种海洋鱼类的肠道内分离、筛选出了产二十碳五烯酸（ＥＰＡ）的细菌．通过苏丹黑染色、测碘值，确定出产脂较高、脂不饱和度高、在ＰＹ海水培养基上生长较好的菌株．ＧＣ分析确定其中３株为产ＥＰＡＭ株，并将其中１株Ｐｊ２０通过ＧＣ／ＭＳ鉴定．这一筛选结果被ＴＬＣ法认同．试验表明，分离自太平洋鲐鱼肠道的Ｐｊ２０菌株，是一种革兰氏阴性、运动性（单极鞭毛）、好气的短杆菌．尚未鉴定其种属． Isolated from several species of marine fish in the intestine, screened out eicosapentaenoic acid (EPA) bacteria. Sudan black staining, measuring the iodine value, to determine a higher lipid production, lipid unsaturation, PY seawater growth medium better strains. Three strains of EPAM were identified by GC analysis, and one strain of Pj20 was identified by GC / MS. This screening result is recognized by the TLC method. Experiments have shown that the Pj20 strain, isolated from the gut of Pacific mackerel, is a Gram-negative, motile (unipolar flagellum), gas-sensitive Brevibacterium. No species has been identified.