Characterization of five psychrotolerant Alcanivorax spp. strains isolated from Antarctica

Five psychrotolerant Alcanivorax spp. strains were isolated from Antarctic coastal waters. Strains were screened for molecular and physiological properties and analyzed regarding their growth capacity. Partial 16S rDNA, alk-B1 and P450 gene sequencing was performed. Biolog EcoPlates and the API 20E test were used to evaluate metabolic and biochemical profiles. Bacterial growth in so-dium acetate was determined at 4, 15, 20, and 25°C to evaluate the optimal temperature. Fur-thermore, the ability of each strain to grow in a hydrocarbon mixture at 4 and 25°C was assayed. Biosurfactant production tests (drop collapsing and oil spreading) and emulsification activity tests (E24) were also performed. Concerning results of partial gene sequencing (16S rDNA, alk-B1 and P450), a high similarity of the isolates with the same genes isolated from other Alcanivorax spp. strains was observed. The metabolic profiles obtained by Biolog assays showed no significant dif-ferences of the isolates compared to the Alcanivorax borkumensis wild type. The results of biodeg-radative tests showed their capability to grow at different temperatures. All strains showed bio-surfactant production and emulsification activity. Our findings underline the importance to pro-ceed in the isolation and characterization of Antarctic hydrocarbon-degrading bacterial strains since their biotechnological and environmental applications could be useful even for pollution re-mediation in polar areas.