Abstract
The purpose of this study was to examine isolation of fuel oil-degrading bacteria for bioaugmentation. Strain KO14-1 was isolated from soil and degraded 84.3％ of n-alkanes in heavy oil A at 25℃, pH7, for 24 hours incubation. The isolate was identified as a species of microbe in genus Acinetobacter by the 16Sr DNA phylogenetic analysis. For investigation of the coexistence influence of other bacteria in the same genus for the n-alkanes decomposing activity of strain KO14-1, competitiveness test with Acinetobacter sp. strains A-1 and/or A-71 with low decomposing activity was carried out. The cell mixture degraded 63.2% of n-alkanes in heavy oil A after 24 hours. After 48 hours the degradation rate finally reached 77.2%. In order to clarify the contributor to the alkane degradation, we investigated the share ratio of each strain by using a terminal restriction fragment length polymorphism (T-RFLP) analysis. The share of strain KO14-1 showed 37.1% at the initial time. It drastically increased to 80.3% after 24 hours and the ratio was maintained for 48 hours. These results indicated that strain KO14-1 was able to be a main contributor to the degradation of n-alkanes in the coexistence system. The high decomposing activity could be provided by this isolate under coexistence of alkane-degrading bacteria in genus Acinetobacter.
