Takahiro Toba

Lactobacillus kefiranofaciens sp. nov. isolated from kefir grains

Lactobacillus kefiranofaciens sp. nov. is described. Four strains of this species isolated from kefir grains are slime-forming, homofermentative, rod-shaped lactic acid bacteria. They differ from all the validly described homofermentative species of the genus Lactobacillus in their carbohydrate fermentation pattern. Their guanine-plus-cytosine content of deoxyribonucleic acid is 34 to 35 mol%. Deoxyribonucleic acids obtained from six other Lactobacillus species do not show significant relatedness to a representative strain of the new species. The type strain of L. kefiranofaciens sp. nov. is WT-2B (ATCC 43761).

Oligosaccharide structures formed during the hydrolysis of lactose by Aspergillus oryzae β-galactosidase

Abstract Di-, tri-, tetra-, penta- and hexasaccharides were formed during the hydrolysis of lactose by transgalactosylation reaction of Aspergillus oryzae β-galactosidase. In this study the isolation and characterization of the major constituents of tri-, tetra- and pentasaccharides are described. The structure elucidation of 3 tri-, 2 tetra- and 1 pentasaccharides was carried out by methylation analysis, mass spectrometry and 13 C-nmr spectrometry. The trisaccharides are O-β- d - galactopyranosyl -(1 → 3)-O-β- d - galactopyranosyl -(1 → 4)- d - glucose (3′- galactosyl-lactose ) , O-β- d - galactopyranosyl -(1 → 6)-β- d - galactopyranosyl -(1 → 4)- d - glucose (6′- galactosyl-lactose ) and O-β- d - galactopyranosyl -(1 → 4)-O-[β- d - galactopyranosyl -(1 → 6)]- d - glucose (4,6- digalactosyl-glucose ) . Tetrasaccharides are O-β- d - galactopyranosyl -(1 → 6)-O-β- d - galactopyranosyl -(1 → 6)-O-β- d - galactopyranosyl -(1 → 4)- d - glucose and O-β- d - galactopyranosyl -(1 → 6)-O-β- d - galactopyranosyl -(1 → 3) [or O-β- d - galactopyranosyl -(1 → 3)-O-β- d - galactopyranosyl -(1 → 6)]-O-β- d - galactopyranosyl -(1 → 4)- d - glucose . Pentasaccharide is O-β- d - galactopyranosyl -(1 → 6)-O-β- d - galactopyranosyl -(1 → 6)-O-β- d - galactopyranosyl -(1 → 6)-O-β- d - galactopyranosyl -(1 → 4)- d - glucose .

Gas-liquid chromatography of trimethylsilylated disaccharide oximes

Abstract The relative retention times of trimethylsilyl derivatives of ten disaccharide oximes on SE-52 and OV-17 liquid phases are reported. Maltose, lactose, gentiobiose, turanose and lactulose gave a single main peak, while the others gave two or three separated peaks which probably resulted from isomeric forms of the sugar oximes.