Toxicity of Ionic Liquids and Organic Solvents towards Escherichia coli and Pseudomonas putida

Abstract

i. AbstractThe University of ManchesterNicola WoodDegree of Doctor of PhilosophyToxicity of Ionic Liquids and Organic Solvents towards Escherichia coli and Pseudomonas putidaFunded by BBSRC2011By turning to biological catalysts such as whole cell microorganisms it is possible to both improve the specificity of a (bio) chemical transformation with the added benefit of reducing the energy demands of a number of synthetic processes which currently use chemical catalysts. The replacement of chemical catalysts with whole cell biological catalysts is often limited by the toxicity of the substrate, side products or end products of a catalytic reaction. The exposure of microorganisms to these products or substrates is usually reflected in phenotypic alterations in membrane of the cell. The techniques of growth data, FT-IR spectroscopy and cluster analysis have been successfully used to establish the phenotypic changes occurring within a microbial culture.The use of microorganisms as replacements for chemical catalysts in synthetic processes may be further increased by the replacement of conventional organic solvents, with a different class of solvents known as ionic liquids.Ionic liquids have been widely reported as 'green' solvents due to their negligible vapour pressure; however reported toxicity testing has demonstrated that many ionic liquid structures have poor toxicity profiles when tested against a range of microorganisms. Due to the large number of ionic liquids which are currently available it is desirable to have a fast and reliable method for initial toxicity screening of many ionic liquids against a wide range of microorganisms. To this end, a simple and cost effective method for ionic liquid toxicity testing using agar diffusion plates and specific growth rates, has been developed and employed to test a wide range of ionic liquid structures against a number of test bacteria.Additionally, the phenotypic changes associated with the exposure of a number of test organisms to a set of both water miscible and water immiscible ionic liquids, have been successfully assessed by FT-IR spectroscopy, cluster analysis, growth data and viable count information, suggesting that this combination of techniques has great potential for future work involving the assessment of phenotypic alterations within microbial cultures.

Date of Award	31 Dec 2011
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Royston Goodacre (Supervisor)