产生物表面活性剂菌SP-7发酵液的性能

The Properties of Bacterial Culture of Biosurfactant-Producing Bacterium SP-7

从胜利油田井口土壤中分离并培育出一株可产生生物表面活性剂的假单胞菌,命名为SP 7,考察了SP 7发酵液作为微生物采油用剂的相关性能。在含各种营养物的培养基中在37℃培养48h的SP 7菌发酵液,与等体积比的胜利河口油田一口井的原油(50℃粘度1019mPa·s)混合,生成O/W乳状液,长时静置后生成下相微乳状液。发酵液的油水界面张力为1.3mN/m。发酵液20℃时生成的泡沫稳定性(半衰期)较商品发泡剂新咪唑啉溶液略差,但50℃时则较好,泡沫体细小致密。发酵液在20～110℃热处理2h后,室温表面张力大体维持恒定(29.7～30.5mN/m);pH值在5.0～10.0范围的发酵液,室温表面张力基本不变(29.7～31.2mN/m);矿化度(NaCl质量浓度)在5.0×103～1.0×105mg/L范围的发酵液,室温表面张力也基本不变(29.7～30.3mN/M),矿化度为1.5×105mg/L时小幅上升至33.3mN/m。从发酵液中提取并纯化的生物表面活性剂,含量为2.1g/L,用IR方法鉴定为脂肽和糖脂,室温时其临界胶束浓度仅为36mg/L。SP 7发酵液可直接用于三次采油。介绍了筛选和培养菌种所用培养基的组成及从发酵液中分离和提纯生物表面活性剂的程序。图3表2参6。

A bacterial strain of Pseudomonas capable of producing biosurfactants is isolated from well site soild at Shengli and grown up, being denoted as bacterium SP7. The properties of bacterial culture (BC) of SP7 as MEOR agent are investigated. When mixed with the crude from a well of Hekow, Shengl (viscosity 1 019 mPa·s at 50℃) in equal volumes, the BC after 48 hrs cultivation at 37℃ in a nutrient medium forms O/W emulsion which gives lower phase microemulsion at long standing. The IFT value between the BC and the crude is of 1.3 mN/m. The BC creates foam with stability (halflife) slightly worse at 20℃ and better at 50℃ than that for 5 g/L foaming agent 'new imidazoline' solution; the foam is dense with small cells. The surface tension of the BC at ambient temperatures does not change practically after the BC thermally treated for 2 hrs at 20—110℃ (29.7—30.5 mN/m) or when its pH value varied in range 5.0—10.0 (29.7—31.2 mN/m) or its salinity (NaCl mass concentration) raised from 5.0×103 to 1.0×105 mg/L (29.7—30.0 mN/m) and slightly increases to 33.3 mN/m with increasing salinity to 1.5×105 mg/L. The biosurfactants extracted from the BC and purified in amount of 2.1 g/L are identified by IR as lipopeptide and glycolipids and possess CMC value at room temperature 36 mg/L only. The BC of SP7 can be used as such in MEOR. The composition of nutrient media for cultivation and fermentation and the procedure of biosurfactant extraction and purification are presented.