Biodegradation of phenol by a newly isolated marine bacterial strain SM5

Abstract

15 bacterial strains were isolated from marine sources on the beef extract-peptone agar plates with 1500 mg/L phenol. Among them, the strain SM5 could tolerate 4500 mg/L phenol on solid beef extractpeptone plates and its phenol biodegradation rate was 96.4% in basal salt (BS) medium under the optimum conditions when the concentration of phenol was 1000 mg/L. These conditions were; initial pH 7.0, 37°C, 3 days, 20 ml medium/50 ml flask and inoculum biomass 12.5% (v/v). Rate of phenol biodegradation of the strain was up to 92.0% under the optimum conditions even when the phenol concentration was increased to 2500 mg/L. Also, the effects of supplement sodium chloride [NaCl (5 to 25 g/L)] on phenol biodegradation were very weak. In this study, a high-efficiency bacterial strain SM5 of phenol biodegradation was obtained from sea mud and could be used for treatment of phenolic water with salt.

Key words: Biodegradation, marine bacterial strain, phenol, isolation.