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A total of 314 strains of Haemophilus, isolated from clinical samples, were studied for the production of beta-galactosidase and beta-xylosidase. None of the H. influenzae strains studied (9 beta-lactamase positive strains and 129 beta-lactamase negative strains) possessed these enzymes. Both enzymes were almost constantly observed among strains of H. paraphrophilus (10 strains studied) and of H. paraphrohaemolyticus (9 strains studied). Among the other species (H. parainfluenzae, 55 strains; H. haemolyticus, 5 strains; H. parahaemolyticus, 97 strains), beta-galactosidase was present in about 30% of the strains studied whereas beta-xylosidase was detected occasionally (3% of the strains studied). Detection of these two enzymes could be a valuable test for the taxonomic study of the genus Haemophilus. However, the type of substrate used for the detection of beta-xylosidase is important: use of the para-nitro-phenyl-beta-xylopyranoside yielded more positive results than the use of its ortho-isomer.

We describe the production of a nonreducing disaccharide consisting of xylose, using β-(1→4)-xylobiose (xylobiose) as substrate, by transxylosylation with A. niger β-xylosidase. This is the first isolation of the nonreducing xylobiose

Enzymatic hydrolysis is one of the most important processes in bioethanol production from lignocellulosic biomass. Acremonium cellulolyticus is a filamentous fungus with high cellulase production but productivity of hemicellulase, especially β-xylosidase, is lower than other filamentous fungi. We identified 2.4 Kb β-xylosidase gene in the A. cellulolyticus genome sequence information and it encoded 798 amino acids without introns. To enhance hemicellulase productivity in A. cellulolyticus, we transformed this fungus with the identified β-xylosidase gene driven by the cellobiohydrolase Ι (cbh1) promoter, using the protoplast-polyethyleneglycol (PEG) method, and obtained a transformant, YKX1. Hydrolysis rate of xylooligosaccharides was more than 50-fold higher using culture supernatant from YKX1 than that from the parental strain, Y-94. Total cellulase activity (measured by filter paper assay) in YKX1 was not affected by the cbh1 promoter used for expression of β-xylosidase, and induced by cellulose. Since YKX1 can produce larger amount of β-xylosidase without affecting cellulase productivity, it is considered to be beneficial for practical monosaccharide recoveries from lignocellulosic biomass.