[reaction: see text] Glucose fatty acid ester synthesis with poly(ethylene glycol)-modified Candida antarctica lipase B (CAL-B) was performed in pure 1-butyl-3-methyl imidazolium tetrafluoroborate [BMIM][BF(4)] (30% conversion) and in pure 1-butyl-3-methyl imidazolium hexafluorophosphate [BMIM][PF(6)] (35% conversion). In a solvent system composed of ionic liquid and 40% t-BuOH conversions up to 90% and isolated yields of up to 89% were achieved using fatty acid vinyl esters as acyl donors and commercial CAL-B.

The influence of the two most commonly used ionic liquids (1-butyl-3-methyl imidazolium tetrafluoroborate, [BMIM][BF(4)], 1-butyl-3-methyl imidazolium hexafluorophosphate, [BMIM][PF(6)]) and three selected organic solvents (dimethylsulfoxide, ethanol, methanol) on the growth of Escherichia coli, Pichia pastoris and Bacillus cereus was investigated. [BMIM][BF(4)] was toxic at 1% (v/v) on all three microorganisms. The minimal inhibitory concentration (MIC) of [BMIM][BF(4)] on E. coli growth was between 0.7 and 1% (v/v). In contrast, [BMIM][PF(6)] was less toxic for P. pastoris and B. cereus, whereas E. coli was not able to tolerate [BMIM][PF(6)] (MIC value: 0.3-0.7% v/v). Growth of P. pastoris was unaffected by [BMIM][PF(6)] at 10% (v/v). Similar results were found for dimethylsulfoxide. Thus, ionic liquids (ILs) can have substantial inhibitory effects on the growth of microorganisms, which should be taken into account for environmental reasons as well as for the use of ILs as co-solvents in biotransformations.

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18‐Methyleicosanoic acid (18‐MEA) is the major fatty acid component linked by a cysteine thioester bond within the cuticle at the surface of hair of humans and animals. An excess of 18‐MEA results in fatty hair and a mild method for enzymatic removal was investigated using a range of commercially available hydrolases. Pure 18‐MEA is available from natural sources only in μg quantities, so it was synthesized in gram‐amounts in a 7‐step chemical synthesis at an overall yield of 34%. Starting from 18‐MEA the corresponding thioester with cysteine (Cys‐18‐MEA) serving as model compound was obtained at a yield of 85%. The detection of hydrolases acting on Cys‐18‐MEA was performed using Ellmanns reagent followed by spectrophotometric quantification of 5‐thio‐2‐nitrobenzoic acid at 410 nm. This led to the identification of 6 enzymes with lipase from Pseudomonas cepacia (Amano PS) as the most active one. With Amano PS, 60% conversion of Cys‐18‐MEA was achieved within 5 h‐reaction time at 30 °C. Preliminary results using samples of human hair were also performed and showed that hydrolytic activity is detectable after incubation of the hair with Amano PS.