Decolorization of Textile Wastewater by Pseudomonas putida: Toxicity Assessment

Textile effluents (TEs) without correct treatment cause high environmental impact because they display several problems mainly due to toxicity and recalcitrance of dyestuffs. The aim of this work was to examine the performance of Pseudomonas putida mt-2 in treating TE. P. putida was able to completely decolorize the studied effluent after 8 h of incubation under agitation in an aerobic bioreactor. Genotoxicity of effluent, before and after biodegradation with P. putida mt-2, was evaluated in vitro using the SOS chromotest and in vivo in mouse bone marrow, by assessing the percentage of cells bearing different chromosome aberrations compared with untreated mice. Results indicated that TE showed a significant ability to induce DNA damage, which was evaluated in both SOS (IF = 3.52) and chromosome aberration assay systems (23.5%). In addition, TE reduced strongly the acetylcholinesterse (60%) and butyrylcholinesterase (51%) activities and induces a remarkable lipid peroxidation effect (increased markedly by approximately fivefold). This toxicity was imputed to the presence of dye compounds of TE. However, toxicity in TE was significantly reduced after 8 h of aerobic incubation with P. putida mt-2 strain. The present study demonstrates that P. putida mt-2, incubated under aerobic conditions, has a metabolism that enables it to degrade TE and, especially, to detoxify the effluent mixtures.