New biobased-zwitterionic ionic liquids: efficiency and biocompatibility for the development of sustainable biorefinery processes. Issue 9 (24th April 2020) - Huet, Gaël
Abstract : A combination of experiments and modeling reveals the influence of alkyl chain lengths in biobased ZILs on the biocompatibility towards various microorganisms. Abstract : A new family of biobased-zwitterionic ionic liquids (ZILs) have been synthesized starting from the renewable resource l -histidine natural amino acid and varying the lengths of the alkyl chains. These ZIL derivatives were firstly studied for their biocompatibility with different microorganisms including bacteria, molds and yeast. The obtained MIC values indicated that all the microorganisms were 5 to 25 times more tolerant to ZIL derivatives than the robust 1-ethyl-3-methylimidazolium acetate [C2 mim][OAc] used as a reference. Modeling studies also revealed that the presence of the cation and the anion on the same skeleton together with the length of the N -alkyl chain would govern the biocompatibility of these neoteric solvents. Among the different synthesized ZILs, the N, N ′-diethyl derivative has been demonstrated to be a suitable eco-alternative to the classically used [C2 mim][OAc] for efficient pretreatment of harwood sawdust leading to a significant improvement of enzymatic saccharification. In addition, with up to a 5% w/v concentration in the culture medium, ZILs did not induce deleterious effects on fermentative yeast growth nor ethanol production.