title: Biodegradation of imidazolium ionic liquids by activated sludge microorganisms.
abstract: Biological properties of ionic liquids (ILs) have been usually tested with the help of standard biodegradation or ecotoxicity tests. So far, several articles on the identification of intermediate metabolites of microbiological decay of ILs have been published. Simultaneously, the number of novel ILs with unrecognized characteristics regarding biodegradability and effect on organisms and environment is still increasing. In this work, seven imidazolium ionic liquids of different chemical structure were studied. Three of them are 1-alkyl-3-methyl-imidazolium bromides, while the other four are tetra- or completely substituted imidazolium iodides. This study focused on the identification of intermediate metabolites of the aforementioned ionic liquids subjected to biodegradation in a laboratory activated sludge system. Both fully substituted ionic liquids and 1-ethyl-3-methyl-imidazolium bromide were barely biodegradable. In the case of two of them, no biotransformation products were detected. The elongation of the alkyl side chain made the IL more susceptible for microbiological decomposition. 1-Decyl-3-methyl-imidazolium bromide was biotransformed most easily. Its primary biodegradation up to 100 % could be achieved. Nevertheless, the cleavage of the imidazolium ring has not been observed.
authors.affiliation: Institute of Fermentation Technology and Microbiology, Lodz University of Technology, ul. Wolczanska 171/173, 90-924, Lodz, Poland. ewa.liwarska-bizukojc@p.lodz.pl.
authors.forename: Ewa
authors.initials: E
authors.lastname: Liwarska-Bizukojc
authors.affiliation: Faculty of Bioscience Engineering, Department of Sustainable Organic Chemistry and Technology, Ghent University, Coupure Links 653, 9000, Ghent, Belgium.
authors.forename: Cedric
authors.initials: C
authors.lastname: Maton
authors.affiliation: Faculty of Bioscience Engineering, Department of Sustainable Organic Chemistry and Technology, Ghent University, Coupure Links 653, 9000, Ghent, Belgium. Chris.Stevens@UGent.be.
authors.forename: Christian V
authors.initials: CV
authors.lastname: Stevens
mesh_terms: D001673:Biodegradation, Environmental; D007093:Imidazoles / Q000737:chemistry*; D052578:Ionic Liquids / Q000737:chemistry*; D013058:Mass Spectrometry; D012722:Sewage / Q000382:microbiology*; D014865:Waste Disposal, Fluid
chemical_list: C575771:1-ethyl-3-methylimidazolium bromide; D007093:Imidazoles; D052578:Ionic Liquids; D012722:Sewage
keywords: Activated sludge; Biodegradation; Imidazolium ionic liquids; Intermediate metabolites; Mass spectrometry