The acylation of a mixture of methyl alpha-D-galacto-, methyl beta-D-gluco- and methyl beta-D-mannopyranosides by octanoic acid was catalysed by lipases from Candida antarctica, Pseudomonas cepacia, Candida rugosa OF or Mucor miehei in acetonitrile at 45 degrees C. The methyl glycopyranosides had the same anomeric configuration as that of the softwood hemicellulose galactoglucomannan. C. rugosa OF lipase had almost no substrate specificity and P. cepacia lipase had a high substrate specificity for the esterification of methyl alpha-D-galactopyranoside.