This study was conducted on the effect of different concentrations of phenanthrene on biodegradation of it
by halophilic bacteria strain in saline conditions. In this study twelve bacterial strains have the ability to degrade
phenanthrene was isolated from saline and sodic soils contaminated with crude oil waste of Sarajeh Qom. QSH1
halophilic strain among isolates showed high ability for degrading phenanthrene and was selected as
superior strain. The effect of different concentrations of phenanthrene (40, 100, 500, 1000 and 2000 mg/L) were
investigated on phenanthrene biodegradation by Q-SH1 halophilic strain in different times including 1, 2, 3, 6
and 10 days. The results showed that the highest amount of phenanthrene biodegradation by Q-SH1 halophilic
strain was observed in 40 mg/L phenanthrene treatment at a rate of 83%. The percent of phenanthrene
biodegradation was decreased with increasing the concentration of phenanthrene. As well as the highest rate of
biodegradation of phenanthrene was 32.7 mg / L.day in 500 mg/L treatment.