Treatment of Olive Mill Wastewaters by Pseudomonas putida mt-2: Toxicity Assessment of Untreated and Treated Effluent

摘要

The aim of this work was to examine the performance of Pseudomonas putida mt-2 in treating olive mill wastewater (OMW) effluent after dilution with sterilized water (33%, v/v) to reduce its bactericide effect. P. putida significantly reduced the color and phenolic compounds in OMW by 75% and 66%, respectively. Dissolved chemical oxygen demand and biochemical oxygen demand removals reached 85.3% and 92.5%, respectively. Genotoxicity of OMW, before and after biodegradation with P. putida mt-2, was evaluated in vitro, using SOS chromotest, and in vivo, in mouse bone marrow, by assessing the percentage of cells bearing different chromosome aberrations. Results indicated that OMW showed a significant ability to induce DNA damage, evaluated by SOS and chromosome aberration assay systems. This toxicity was imputed to the presence of phenolic compounds of OMW. However, the toxicity of OMW was significantly reduced after 48 h of aerobic incubation with P. putida mt-2. The present study demonstrates that P. putida mt-2, incubated under aerobic conditions, has a metabolism that enables it to degrade OMW and, especially, to detoxify the effluent mixtures.