Transglycosylation of Phenols by Endo-1, 4-β-galactanase from Penicillium citrinum and Several, β-Galactosidases

Transfer reactions of an endo-1, 4-β-galactanase from Penicillium citrinum and several β-galactosidases were studied using aryl compounds as acceptors. The acceptor specificity of the galactanase was much broader than those of β-galactosidases from Escherichia coli, Penicillium multicolor, Bacillus circulans and Aspergillus oryzae : Various hydroxybenzenes and hydroxybenzoic acids acted as acceptors for the galactanase, although most of them were poor or ineffective for the, β-galactosidases. Carboxyl group adjacent to OH groups reduced effectiveness as acceptors for both the enzymes. Benzyl alcohol and hydroxybenzyl alcohols were good acceptors for the enzymes. The transfer ability of galactanase was compared in detail with the β-galactosidases using 1, 3-dihydroxybenzene (2) as an acceptor. The galactanase formed the transfer products much more effectively than the β-galactosidases at 0.5-3% of the acceptor concentrations. Increasing activity of the galactanase and prolonged reaction time resulted in an increase of the transfer products. Increasing activities of β-galactosidases and longer incubation times reduced the yields due to rapid hydrolysis of the aryl galactoside formed.