Microbial Adaptation to Ionic Liquids Increases the Talent to Treat Contaminants

Pseudomonas stutzeri strains are able to remediate different persistent contaminants, although they fail to treat efficiently industrial dyes. In this work, we have demonstrated that the acclimation of a Pseudomonas strain to the presence of the ionic liquid 1-ethyl-3-methyl imidazolium ethylsulfate can be a solution to remove two synthetic dyes widely found in wastewater effluents from textile industry: Acid Black 48 (AB48) and Reactive Black 5 (RB5), as model anthraquinone and diazo dyes, respectively. The remediation values achieved at small scale for both contaminants (individually and mixed) were higher than 75% in just 2 days. The process was scaled-up in a stirred tank bioreactor, and the levels of removal (greater than 80%) allowed confirming the suitability of the selected bioreactor configuration. All the obtained biomass and dye removal data were modeled by fitting to well-known equations in order to shed more light on the characteristics of the biotreatment process. The present work is the basis for the use of this microorganism at industrial scale, where different pollutants are found simultaneously in the same effluent.