An ideal strain for crude oil degradation in saline soils would be one with high salt-tolerance. A novel bacterial strain, Serratia sp. BF40, was isolated from crude oil contaminated saline soils. Its salt-tolerance, surface activity and ability to degrade crude oil in saline soils were evaluated. It can grow in liquid culture with NaCl concentration less than 6.0%. Its surface activity characterized as an efficient surface tension reduction, was significantly affected by salinity above 2.0%. BF40 inoculation could decrease surface tension of soil solutions and facilitate crude oil removal in soils with 0.22-1.20% salinity, but the efficiency was both significantly lower than its biosurfactant addition. The BF40 strain has a high potential for biodegradation of crude oil contaminated saline soils in view of its high surface activity and salt-tolerance, which is the first report of biosurfactant producing by the genus Serratia for petroleum degrading. We suggest that biosurfactant addition is an efficient strategy. Simultaneously, the growing status of the strain and how to boost its surface activity in saline soils should deserve further studies in order to achieve a continuous biosurfactant supply.

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