Bioremediation of phenol contaminated effluents by two bacterial strains isolated from polluted environments.

CINTIA E. PAISIO ; MELINA A. TALANO; MARÍA INÉS MEDINA; ELIZABETH AGOSTINI

Congreso; VIII Congreso Argentino de Microbiología General “SAMIGE; 2012

Phenols, produced and released by different industries, may interfere with the ecosystem equilibrium because they are highly toxic. Biodegradation is recognized as a sustainable process of wastewater treatment, which can promote an efficient reduction of organic matter content with minimal energy requirements and therefore, low costs of implementation. Acinetobacter sp. RTE1.4 and Rhodococcus sp. CS1, strains used in this work, were isolated from a chemical industry effluent and tannery sediments, respectively. These strains were selected for their ability to degrade phenol with high efficiency. The aims of this work were: a) to determinate the ability of the strains to grow and degrade phenols contained in different effluents, and b) to evaluate their efficiency of remediation through Chemical Oxygen Demand (COD) and Biological oxygen Demand (BOD) determinations. In this work, bioremediation of four effluents was studied: three derived from chemical plants and one from a tannery. The strains were initially tested for their tolerance to these effluents evaluating their growth in agar plates containing pure effluents (100%) and diluted with sterile distilled water (25, 50 and 75% V/V). Both strains were able to grow in all pure effluents. Subsequently, phenol biodegradation studies were carried out in Erlenmeyer flasks containing the effluents supplemented with different initial phenol concentrations (200, 600 and 1000 mg/L). Bacterial biomass and phenol consumption was determined. Acinetobacter sp. RTE1.4 degraded 200 and 600 mg/L of phenol, after three and five days, respectively whereas Rhodococcus sp. CS1 was able to completely degrade 200 and 1000 mg/L of the contaminant in the same time period. Non-inoculated controls were also performed to establish the remediation carried out by the native microorganisms and in these controls a degradation of phenol was not detected. Moreover, a significant reduction in COD and BOD values was observed in the effluents treated with both strains. In conclusion, Acinetobacter sp. RTE1.4 and Rhodococcus sp. CS1 could be appropriate microorganisms for effective bioremediation of different effluents, contaminated with phenols.