Abstract
A screening of nine ionic liquids (ILs) has been carried out in order to study the influence of the ILs anion’s and cation’s nature and structure on the synthesis of mannosyl myristate catalyzed by Novozym® 435. The best ILs in terms of yield (η) and initial rate (v0) are those based on the TFO- anion. The 24h-yield (24h-η) reached 64.9% in [Bmim][TFO] and 70.9% in [Bmpyrr][TFO] by transesterification while it reached 29.7% and 44.5% respectively in each IL by esterification. [Bmpyrr][TFO] based on the pyrrolidinium cation gave the best results although this cation has been rarely used for biocatalysis. This work has thus highlighted a cation that could be further studied for the biocatalysis of glycosylated compounds. The study of the relationship between the structure of the ILs and the v0 and η for the biocatalysis of mannosyl myristate showed that the lipase effectiveness is influenced by the anions while the cations have an indirect influence on the interaction strength between Novozym® 435 and the anions.
Keywords: Acylation, biocatalysis, carbohydrates, green chemistry, ionic liquids, Novozym® 435, mannosyl myristate, sugar esters.