THE SCREENING OF BACTERIA PRODUCING BIO-SURFACTANT AND THE ANALYSIS OF ITS METABOLITE

摘要

From the dehydrate and degasification crude oil in oilfield union station, two bacterial strains which have a good ability to degrade oil and produce bio-surfactants were isolated, named D1 and D2. The adaptability evaluation of the stratum condition showed that the formation water, indigenous microbes and the screened strains were matching well and the total numbers of bacterium could reach 106 cells/ml under 73 culture temperature ℃ . Wherein, the bacterial fermentation broth using un-sterilized formation water had a better effect on oil emulsification and dispersing. The surface tension of crude oil having been treated decreased from 70.8 mN/m to 59.0 mN/m and 65.3mN/m separately, the degenerate rate were 11.15% and 12.1% correspondingly. Gas metabolizing analysis showed that the existence of the crude oil and liquid paraffin had no distinct effects on microbial gas-produced. Bio-surfactants were collected from the fermentation broth with strain D1 and D2 could cut down the surface tension of organic phase greatly, from 64.5 mN/m to 54.56 mN/m,66.4 mN/m to 55.9 mN/m separately. The bio-surfactant was determined as lipoid mainly.