抄録
Degradation of three kinds of crude oils such as Arabian light, Berni and Murban crude oil by a pure bacterial strain, Caulobacter sp., and by mixed culture integrated from the sea water sampled at Kawasaki Harbor was studied experimentally in the enriched seawater (ESW) medium.
The degradation of oils were determined in total residual oil and in four fractions of saturated, aromatics, asphaltene and column residue by use of column chromatography.
The saturated fraction was most biodegradable and the aromatics followed for all three crude oils in both pure and mixed cultures. The asphaltene and the column residue were not degraded apparently by microorganisms in 30 days incubation. Crude oils in pure culture were degraded from 30 to 36 percent and 45 to 55 percent in mixed culture. Activities of oil degradation were higher in mixed culture. Average degradation rates of crude oil for the duration of rapid disappearance of oil were calculated to be in a range from 4.92 to 5.83 mg-oil l-1h-1 for pure culture and from 15.1 to 19.4 mg-oil l-1h-1 for mixed culture. Relative degradation of n-paraffin of different carbon numbers in saturated fraction was similar in both cultures.
