Potential biodegradation of crude petroleum oil by newly isolated halotolerant microbial strains from polluted Red Sea area

• Novel microbial strains were isolated from crude oil-contaminated Red Sea water.
• The strains were identified as Lipomyces tetrasporus and Paecilomyces variotii.
• Both isolates degraded the total petroleum hydrocarbons by more than 55%.
• L. tetrasporus tolerate 45 g/L salt and maintain its biodegradation efficiency.
• The consortium approach improved the biodegradation ability.

Two microbial isolates from oil polluted Red Sea water in Egypt, designated as RS-Y1 and RS-F3, were found capable of degrading Belayim mix (BX) crude oil. Strains RS-Y1 and RS-F3 were assigned to the genera Lipomyces tetrasporus and Paecilomyces variotii based on their morphological and physiological characteristics. Both isolates were compared for the biodegradation of crude petroleum-oil hydrocarbons in basal salt medium supplemented with 5% (w/v) of BX-crude oil. Gas chromatography profile showed that the biodegradation of total petroleum hydrocarbons (TPHs) inoculated with L. tetrasporus (68.3%) and P. variotii (58.15%) along with their consortium (66%) significantly reduced TPHs levels as compared to the control after 30 days. L. tetrasporus (44.5%) was more effective than P. variotii strain (32.89%) in reducing the unresolved complex mixtures (UCM) content from the medium. Both isolates exhibited a strong growth over a wide range of salinity (5–45 g/L NaCl).