Biodegradation of phenol by pseudomonas aeruginosa, acinetobacter sp. and stenotrophomonas maltophilia isolated of the sludge activated of a steel industry

The purpose of this work was to study the degradation capacity of phenol by strains of Pseudomonas aeruginosa, Acinetobacter sp. and Stenotrophomonas maltophilia isolated from activated sludge from a steel industry. For this, a study of the kinetics of microbial growth and degradation of phenol, besides a factorial planning was carried out, varying the initial concentration of phenol and the pH. Pseudomonas aeruginosa removed 100% of the phenol in 72 h, when the initial concentration of the compound was 250 mg L-1 and the pH was controlled at 6.4. The bacterium Acinetobacter sp. removed 68.71 (± 0.51) % of the phenol and the S. maltophilia strain removed 68.55 (± 0.58) % of the phenol in 96 hours under the same conditions as the assay performed with the P.aeuruginosa strain. It was found that the optimum pH for the removal of phenol by P. aeruginosa was 6.4, for Acinetobacter sp. was 7.0 and S. maltophilia was 7.3. The removal of phenol by the three bacteria was better when the initial phenol content was lower, with the P. aeruginosa bacterium having the best performance and showing promising results even when there were higher initial concentrations of phenol. This work brings the possibility of a process of great environmental interest, since phenol is a recalcitrant compound of great environmental impact and the bacteria isolated from the activated sludge of a steel industry are able to biodegrade phenolic compounds and can be used in treatment effluents or in bioremediation techniques.