从北极环境中筛选并鉴定产EPA的细菌资源

Screening and characterization of EPA-producing Arctic bacteria

为筛选出高产二十碳五烯酸(EPA,C20∶5)野生型菌株,以采自北极地区的176株细菌为材料,通过TTC(2,3,5-氯化三苯基四氮唑)显色法和气相色谱两种方法筛选出4株疑似产EPA的细菌,并通过气质联用进一步确认其产物为EPA。其中编号6-42的菌株EPA占总脂肪酸百分比含量最高(4.9%),经16S r DNA进化分析鉴定为希瓦氏菌(Shewanella baltica),并命名为S.baltica 6-42。通过研究温度和浅蓝菌素等培养条件对其EPA含量的影响,发现加入3μg/m L的浅蓝菌素后,0℃静置培养其EPA的总脂肪酸百分比含量和单位干菌含量最高,分别为11.5%和6.7mg/g,10℃振荡培养其单位体积培养液EPA含量最高为3.6mg/L。

To identify wild bacteria with high yield of eicosapentaenoic acid（EPA）,gas chromatography and2,3,5-triphenyltetrazolium chloride（TTC） methods were used to select 176 strains from the Arctic area. Four EPA-producing bacteria strains were obtained and further confirmed by gas chromatography and mass spectrometry（GC-MS）. Among them,strain 6-42 had the highest EPA content（up to 4. 9% of total fatty acids） which was identified as Shewanella baltica by 16 S r DNA sequencing. The strain was named as S. baltica 6-42. Temperature and cerulenin effects were investigated. Results showed that in 3 μg/m L cerulenin at 0℃,the EPA content and EPA titerof S. baltica 6-42 reached 11. 5% and 6. 7 mg/g,respectively. When cultured at 10℃ with shaking,3.6 mg/L EPA were yielded.