Impact of selected anions and metals on the growth and in vitro removal of methylmercury by Pseudomonas putida V1

The aim of this study was to evaluate the influence of plant nutrients (nitrate, phosphate, sulfate and molybdate), NaCl and heavy metals (lead, copper, chromium and nickel) on the growth and methylmercury removal by Pseudomonas putida V1 in vitro. The growth and methylmercury removal capacity of P. putida V1 were evaluated in Luria Bertani (LB) broth containing different doses of plant nutrients (50-300 mmol L-1); NaCl (0.5-20%) and heavy metals (100 and 600 mu mol L-1). The analyses of the residual mercury were carried out in an atomic absorption/cold steam spectrophotometer. The results indicated a significant decline in the methylmercury removal from LB broth (p < 0.05) in the presence of the plant nutrients concentrations tested, however the growth of this bacteria was affected only in few conditions. P. putida V1 was capable of removing methylmercury in the presence of 10% NaCl. The concentrations of lead or copper tested and the addition of 2.3 mu mol L-1 of methylmercury was highly inhibitory to growth of P. putida V1. In presence of 0.008 mu mol L-1 of methylmercury and lead, this bacteria was able to remove 89% of methylmercury, whereas in the presence of copper it only removed between 45% and 12%. The resistance of P. putida V1 to NaCl and to some metals suggests the potential use of this microorganism in bioremediation processes of areas contaminated with these substances. (C) 2014 Elsevier Ltd. All rights reserved.