title: Hormetic effect of ionic liquid 1-ethyl-3-methylimidazolium acetate on bacteria.
abstract: The biological effect of ionic liquids (ILs) is one of the highly debated topics as they are being contemplated for various industrial applications. 1-ethyl-3-methylimidazolium acetate ([EMIM][Ac]) showed remarkable hormesis on anaerobic Clostridium sp. and aerobic Pseudomonas putida. Bacterial growth was stimulated at up to 2.5 g L(-1) and inhibited at >2.5 g L(-1) of [EMIM][Ac]. The growth of Clostridium sp. and P. putida were higher by 0.4 and 4-fold respectively, in the presence of 0.5 g L(-1) [EMIM][Ac]. Assessment of the effect of [EMIM][Ac] under different growth conditions showed that the hormesis of [EMIM][Ac] was mediated via regulation of medium pH. Hormetic effect of [EMIM][Ac] was evident only in medium with poor buffering capacity and in the presence of a fermentable substrate as the carbon source. The hormetic effect of [EMIM][Ac] on bacterial growth is most likely associated with the buffering capacity of acetate anion. These observations have implications in ILs toxicity studies and ecological risk assessment.
authors.affiliation: Biofouling and Biofilm Processes Section, Water and Steam Chemistry Division, Bhabha Atomic Research Centre, Kalpakkam 603102, Tamil Nadu, India. Electronic address: venkatany@gmail.com.
authors.forename: Y V
authors.initials: YV
authors.lastname: Nancharaiah
authors.affiliation: Environmental Sciences Department, Brookhaven National Laboratory, Upton, NY 11973, USA; Division of Advanced Nuclear Engineering, POSTECH, Pohang, Republic of Korea.
authors.forename: A J
authors.initials: AJ
authors.lastname: Francis
mesh_terms: D003013:Clostridium / Q000187:drug effects* / Q000254:growth & development; D059165:Hormesis / Q000187:drug effects*; D006863:Hydrogen-Ion Concentration; D007093:Imidazoles / Q000494:pharmacology*; D052578:Ionic Liquids / Q000494:pharmacology*; D016958:Pseudomonas putida / Q000187:drug effects* / Q000254:growth & development; D018570:Risk Assessment
chemical_list: D007093:Imidazoles; D052578:Ionic Liquids; C518739:1-ethyl-3-methylimidazolium
keywords: 1-Ethyl-3-methylimidazolium acetate; Biomass pretreatment; Clostridium sp.; Hormesis; Imidazolium ionic liquids; Pseudomonas putida