|Cote, Gregory - Greg|
Submitted to: Journal of Molecular Catalysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/27/2004
Publication Date: 7/28/2004
Citation: Kremnicky, L., Mastihuba, V., Cote, G.L. 2004. Trichoderma reesei acetyl esterase catalyzes transesterification in water. Journal of Molecular Catalysis. 30(5-6):229-239. Interpretive Summary: In recent years, there has been much interest in the use of biocatalyst (enzymes) for carrying out chemical reactions. The use of biocatalysts can help minimize the use of toxic or dangerous chemicals in certain reactions. However, many of these biocatalyic reactions still rely on the use of chemical solvents. This work describes the use of a novel enzyme to carry out similar reactions using water as the solvent, thus taking the use of biocatalysts to an even safer and more environmentally friendly level.
Technical Abstract: Partially purified Trichoderma reesei RUT-C30 acetyl esterase preparation was found to catalyze acyl transfer reactions in organic solvents, mixtures of organic solvents with water, and even in water. Using different acyl donors, the best results for acetyl transfer in water were obtained using vinyl acetate. As acetyl acceptors, a variety of hydroxyl bearing compounds in aqueous solutions was used. Degree of conversion and the number of newly formed acetates varied according to the acceptor used. Conversions over 50% were observed for the majority of several common monosaccharides, their methyl and deoxy derivatives, and oligosaccharides. In several cases, the transesterification reaction exhibited strict regioselectivity, leading to only one acetyl derivative. Preparative potential of the transesterification in water was demonstrated by transacetylation of methyl beta-D-glucopyranoside, 4-nitorphenyl beta-D-glucopyranoside, and kojic acid, yielding 56.4% of methyl 3-O-acetyl beta-D-glucopyranoside, 70.2% of 4-nitrophenyl 3-O-acetyl beta-D-glucopyranoside, and 30.9% of 7-O-acetyl-kojic acid as the only reaction products. This new enzymatically catalyzed transacetylation in water opens a new area in chemoenzymatic synthesis. Its major advantages are simplicity, highly regioselective esterification of polar compounds, high yields, low enzyme consumption, and elimination of the need to use toxic organic solvents.