The Journal of

Introduction: Petroleum hydrocarbons are the most frequent environmental pollutants. Contamination of soil and groundwater by diesel released from underground storage tanks is an important and extensive environmental problem in Iran. The aim of this study was to isolate and molecular identification of n-hexadecane-degrading bacteria from compost.

Methods:Hexadecane, C₁₆H₃₄, used as a model contaminant of diesel oil. New n-hexadecane degrading bacteria was  isolated from compost by using enrichments on n-hexadecane. Then isolated bacterium was identified by PCR with 16S rDNA method. Then n-hexadecane degradation was tested by isolated bacteria. Finally response of strain to different salinity concentrations (0, 1, 2.5 and 5) was determined.

Results:Based on morphology, biochemical tests, 16S rDNA sequence analysis and phylogenetic characteristics, the isolated bacteria were identified as Serratia marcescens. After 33 days, n- Hexadecane concentration decreased from 90 mg to 32.84 mg (63.51%) by isolated bacteria. In addition, the results showed that isolated bacteria can grow on 5% salinity.

Conclusion:The results of this study show that Serratia marcescens can be used in remediation of petroleum products especially diesel oil in tropical area and semisalinity of soils in Iran. Our findings indicate that Serratia marcescens is a halotolerant microorganism.