Effect of Adding Rhamnolipid Biosurfactant and Inoculating Rhamnolipid-producing Strain on Oil Biodegradation

The effect of adding rhamnolipid and inoculating biosurfactant-producing strain to the biodegradation system of petroleum hydrocarbons was investigated. The addition of rhamnolipid increased the biodegradation extent of total petroleum hydrocarbon from 35.7% to 57.6% within 20 days. The biodegradation rates of both saturate and aromatic fractions were enhanced.Biosurfactant-producing strain O-2-2 could utilize saturate fractions of crude oil and excrete rhamnolipid biosurfactant,resulting in a higher biodegradation of total petroleum hydrocarbon. Co-inoculating biosurfactant-producing strain O-2-2 could enhance the biodegradation of saturate fractions greatly,but decrease that of aromatic fractions,which indicated that there might be competition between biosurfactant-producing strain and the hydrocarbon-degrading consortium.