Ionic liquids in whole-cell biocatalysis: a compromise between toxicity and efficiency

Abstract

Comparison of chemical catalysis by metal complexes, enzymatic catalysis and whole-cell biocatalysis shows well-addressed advantages of the latter approach. However, a critical limitation in the practical applications originates from the high sensitivity of microorganisms to the toxic effects of organic solvents. In the present review, we consider toxic solvent properties of ionic liquid/water systems towards the development of efficient applications in practical organic transformations.

Synthesis, self-assembly, bacterial and fungal toxicity, and preliminary biodegradation studies of a series ofl-phenylalanine-derived surface-active ionic liquids

“…imidazolium and cholinium SAILs (25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40) are provided in Table S4 and Fig. 3b,c.…”

“…31 Hence, gathering of additional ecotoxicity data is essential to ascertain the balance of toxicity vs efficiency. 32 An imbalance in the IL research field between the assessment of the environmental impacts of ILs and the impact of manufacturing ILs has recently been pointed out.. 33 Some confusion has arisen from the estimation of the ready biodegradability test as an indicator for ultimate degradation, whereas the life cycle assessment is often considered as a "gold standard method" for determining whether a method or technology is green. Therefore, when designing a new green ILs, undertaking a comprehensive yet feasible green chemistry assessment, still remains a major challenge.…”

An Overview on the Toxicological Properties of Ionic Liquids toward Microorganisms

“…The toxic effects of ILs for biocatalytic purposes are said to depend on the length of the alkyl chain in the cation, as well as the nature of the cation and anion. Generally, cholinium ILs and imidazolium‐based ILs with short alkyl chains represent the systems of choice for application in whole‐cell biocatalysis . On the other hand, among the different anions, Cl − seemed the best choice for microorganisms in whole cell system.…”

“…[106] The use of ILs in whole-cell biocatalysis has attracted great attention to overcome the problem associated with organic solvents, including a negative effect on both enzymes and microorganisms. [107,108] The molecular elasticity of ILs do indeed make them an ideal platform for optimizing the substrate solubilities needed for any biocatalytic reaction. [108] In addition, the application of ILs can compromise between process efficiency and toxicity effects toward enzymes.…”

“…Generally, cholinium ILs and imidazolium-based ILs with short alkyl chains represent the systems of choice for application in whole-cell biocatalysis. [107] On the other hand, among the different anions, Cl − seemed the best choice for microorganisms in whole cell system. In addition, hydrophobic ILs are found to be a promising and attractive replacement for molecular solvents in whole-cell biotransformation.…”