Removal of Phenol Using Spore Forming <i>Bacillus</i> ABO11 Isolated from Waste Water Treatment Plant

Abstract

Twenty isolates of bacteria were isolated from contaminated wastewater collected from wastewater treatment station, used to clean the raw sewage at Jeddah on minimal medium containing phenol (0.5 g/l) as carbon source while at 0.6 g/l phenol, five isolates belonging to Gram positive and Gram negative bacteria were obtained after 10 days of growth at 37°C. All the tested bacteria were tested for phenol degradation in liquid medium and isolate ABO11 was the most active isolate in phenol degradation. It was selected and tested for the ability to use phenol as carbon and energy source. It was identified as Bacillus sterothermophilus ABO11 using morphological and biochemical tests. Genetic studies confirmed the identification. Bacterial growth and phenol degradation by the selected bacterium were determined using different initial phenol concentrations (0 - 1.0 g/l). Very weak growth was recorded at 0.8 g/l and no growth or degradation was observed at higher phenol concentration. The isolate was adapted to grow in presence of 0.8 g/l phenol and phenol degradation was checked up to 12 days of growth. Percentage of degradation was 100% after 10 days. Maximum growth was observed at 40°C, pH 8 and using NH 4 Cl as nitrogen source. In conclusion, the selected isolate, Bacillus sterothermophilus ABO11 can be used in protecting the environment from phenol pollution.