Abstract:

Cultured with enrichment technology, a high desulfurization strain TV9704 was further selected from the 21 desulfurization bacteria separated from oilcontaminated soil samples of the Jidong Oilfield and Shengli Oilfield. The strain TV9704 does not use dodecane, hexadecane, liquid paraffin, diesel and naphthalene as carbon source and energy for its growth, therefore the oil consumption value was not obviously decreased; comparatively, thiophene or dibenzothiophene(DBT) was the only carbon source, sulfur source and energy source. In the experiment, the concentration of thiophene or DBT was measured by UV spectrophotometer. After 48 hs and 144 hs cultured with culture medium of initial concentration of 632 mmol/L, the degradation rate of thiophene by the strain TV9704 was 390% and 638% respectively. After 72 hs cultivation, the degradation of DBT by the strain TV9704 (initial concentration of 27 mmol/L) was 124 mmol/L. Using glycerol and sodium acetate as carbon source, the degradation rate of DBT was significantly increased by ethanol. Identified by China Industrial Culture Collection Center(CICC), the strain TV9704 was classified as Bacillus sp, with the characteristics of grampositive, obligate aerobic, and a circular orange colony formed on the panel covered with nutrition gravy. With the 16SrNDA gene sequencing test and analysis, the homology of the strain TV 9704 to Bacillus aquimaris and Bacillus misflav was 992% and 982%, respectively. However, their cell morphology as well as their physiological and biochemical characteristics were very different from each other. We suppose the strain TV9704 to be a fresh new genus since it is impossible to categorize it to any population.

Key words:

 Biodesulfurization; strain; thiophene; dibenzothiophene; screening; Bacillus sp