Biodegradation of imidazolium ionic liquids by activated sludge microorganisms.

Ewa Liwarska-Bizukojc,Christian V Stevens,Cedric Maton

doi:10.1007/s10532-015-9747-0

Ewa Liwarska-Bizukojc, Christian V Stevens + Show 1 more

Open Access

https://doi.org/10.1007/s10532-015-9747-0

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Journal: Biodegradation	Publication Date: Oct 13, 2015
Citations: 59	License type: CC BY 4.0

Affiliation: Lodz University of Technology, Ghent University

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.Electronic supplementary materialThe online version of this article (doi:10.1007/s10532-015-9747-0) contains supplementary material, which is available to authorized users.

Highlights

Ionic liquids, because of their unique physicochemical properties, are a promising group of chemicals that can be widely used in various branches of industry
The results presented by Romero et al (2008) revealed that 1-alkyl-3-methyl-imidazolium chlorides were poorly biodegradable even if the additional carbon source, in this case glucose, was available
The main aim of this work was to identify the products of biodegradation of seven imidazolium ionic liquids, including three conventional 1-alkyl-3methyl-imidazolium bromides and four novel, recently synthesized peralkylated ILs

Summary

Introduction

Because of their unique physicochemical properties, are a promising group of chemicals that can be widely used in various branches of industry. These compounds have been investigated intensively for the last two decades with regard to their biological properties and their effect on the environment (Jastorff et al 2003; Gathergood et al 2006; Stolte et al 2008; Coleman and Gathergood 2010; Pham et al 2010; Siedlecka et al 2011; Markiewicz et al 2013). In order to evaluate biodegradability of ILs, standard OECD tests were usually applied They revealed that many of the ionic liquids were not susceptible to biological decomposition. Standard biodegradation tests focused mainly on primary biodegradation, which is an alteration in the chemical structure of a substance, by the biological action, resulting in the loss of the specific property of that substance (OECD 2014)

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