Enhanced isolation and culture of highly efficient psychrophilic oil-degrading bacteria from oil-contaminated soils in South Korea

It is known that isolation of oil-degrading bacterial strains is difficult at low temperatures, and the biodegradation efficiency of oil-contaminated soil is significantly reduced in cold weather. In this study, 14 strains were isolated from oil-contaminated soil that grew well at 10 degrees C by using a newly developed culture method.11 of the 14 isolates were successfully cultured in mineral salts medium containing 1,500 ppm of oil components, 500 ppm each kerosene, gasoline, and diesel as carbon sources, at 10 degrees C for 2 weeks. The oil degradation efficiencies of these 11 isolates ranged from 36% to 100%, as measured by total petroleum hydrocarbon (TPH) degradation analyses. Three strains (Pseudomonas simiae G1-10, P. taiwanensis Y1-4, and P. koreensis Gwa2) displayed complete degradation (100%), and six others (P. frederiksbergensis G2-2, P. arsenicoxydans Y2-1, P. umsongensis Gwa3, P. migulae Gwa5, Rhodococcus jialingiae Y1-1, and R. qingshengii Y2-2) showed relatively high degradation efficiencies (> 70%). This study suggests that these isolates can be effectively utilised in the treatment of oil-contaminated soil in landfarming, especially during winter.