Biodegradation of thiomersal containing effluents by a mercury resistant Pseudomonas putida strain

Raquel Fortunato, João G. Crespo, M. A. M. Reis

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4 Citations (Scopus)


Thiomersal, a toxic organomercurial with a strong bactericidal effect, is the most widely used preservative in vaccine production. As a result, vaccine production wastewaters are frequently polluted with thiomersal concentrations above the European limit for mercury effluent discharges for which there is, presently, no remediation technology available. This work proposes a biotechnological process for the remediation of vaccine production wastewaters based on the biological degradation of thiomersal to metallic mercury, under aerobic conditions, by a mercury resistant bacterial strain. The kinetics of thiomersal degradation by a pure culture of Pseudomonas putida spi3 was firstly investigated in batch reactors using a thiomersal amended mineral medium. Subsequently, a continuous stirred tank reactor fed with the same medium was operated at a dilution rate of 0.05 h-1, and the bioreactor performance and robustness was evaluated when exposed to thiomersal shock loads. In a second stage, the bioreactor was fed directly with a real vaccine wastewater contaminated with thiomersal and the culture ability to grow in the wastewater and remediate it was evaluated for dilution rates ranging from 0.022 to 0.1 h-1.

Original languageEnglish
Pages (from-to)3511-3522
Number of pages12
JournalWater Research
Issue number15
Publication statusPublished - 1 Sept 2005


  • Bioremediation
  • Organic mercury
  • Pseudomonas
  • Thiomersal
  • Vaccine wastewaters
  • Wastewater treatment


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