Environmental Concerns Regarding Ionic Liquids in Biotechnological Applications

An Overview on the Toxicological Properties of Ionic Liquids toward Microorganisms

“…It was found that they exhibited different level of sensitivity to ILs in terms of growth kinetics and viability. Three debatable notions have noticed from different studies: i) there are differences between the effects of ILs on Gram-positive and Gram-negative bacteria, [16,26,[74][75][76] ii) no discernible difference between the effects on the two types of bacteria, [3,77,78] iii) insufficient evidence to draw definitive conclusions on the effects on the bacteria types. [25,79] For example, Gram-positive B. subtilis was more resistant to imidazolium-based hydrophilic ILs, whereas Gramnegative Pseudomonas aeruginosa exhibited more tolerance to choline-and phosphonium-based ILs.…”

“…[84] Furthermore, cations like morpholinium and cholinium have been found to be the least toxic, and can be used to design inherently safe ILs, especially when combined with short polar side chains and nontoxic anions. [26,[85][86][87][88] The oxygenated group in the cation also decreases toxicity as it contributes to hydrophilicity. Mustahil et al [87] reported new antimicrobial surface active ILs with cations named pyrrolidinium, imidazolium, pyridinium, piperidinium, morpholinium, and cholinium, and lauroyl sarcosinate as an anion.…”

“…[3,80,86] To obtain low toxicity, good stability, and biological activity, anions derived from naturally occurring substances are suitable as counterions to prepare ILs. [12,86] Some examples of natural bio-based anions in the third-generation ILs include lactic acid, nicotinic acid, oleic acid, pelargonic acid, acetic acid, salicylic acid, [12] amino acid, [4,26] and fatty acid. [89] In a recent study, [12] the third-generation protic ILs were synthesized using an herbicide, thifensulfuronmethyl (TFM).…”

“…The differences in cell wall composition play an important role in the interaction between ILs and bacterial cell walls. [3,16,25,26] Several reviews have focused on the toxicity and biodegradability of ILs. [15,[27][28][29][30] Here, we provide an overview of the most recent findings with emphasis on thirdgeneration ILs.…”

Cholinium-Based Ionic Liquids as Promising Antimicrobial Agents in Pharmaceutical Applications: Surface Activity, Antibacterial Activity and Ecotoxicological Profile

“…However, significant drawbacks have already been observed mainly related to their toxicity and persistence [ 20 , 21 ]. Many ILs displayed significant toxicity towards enzymes, microorganisms, and cells, in addition to animals and plants [ 22 , 23 ]; and most are not easily biodegradable [ 24 ]. In addition, recent studies have reported the multiplication and dissemination of antibiotic resistance genes by some persistent imidazolium-based ILs because of enhanced horizontal gene transfer, while other similar structures, such as biocidal quaternary ammonium compounds, have long been found to contribute to the rise of antibiotic resistance [ 25 ].…”