Disaccharides permeases: constituents of xylanolytic and mannanolytic systems of Aureobasidium pullulans

Aureobasidium pullulans, a yeast-like microorganism was found to produce ma nnobiose permease and xylobiose permease, transporting beta-1,4-mannobiose or beta-1,4-xylobiose into the cells from extracellular media. Both permeas es are induced by the same inducers as the corresponding hemicellulolytic e nzyme systems. Mannobiose permease is induced by beta-1,4-mannobiose or is formed in the cells growing on mannan (inducers of beta-mannanolytic enzyme s) and xylobiose permease is induced by D-xylose, beta-1,4-xylobiose or dur ing the growth on xylan (inducers of xylanolytic enzymes). The permeases ar e energy dependent, synthesized de novo and their activities are inhibited by D-glucose. Since mannobiose permease transports beta-1,4-mannobiose, xyl obiose permease appears to be less specific and transports beta-1,4-mannobi ose, beta-1,4-xylobiose and methyl beta-D-xylopyranoside. Methyl beta-D-man nopyranoside or methyl beta-D-xylopyranoside serve as less efficient induce rs of the corresponding permeases than beta-1,4-mannobiose or beta-1,4-xylo biose. (C) 1998 Elsevier Science B.V. All rights reserved.