Abstract: In this paper,the effects of three carbon sources,namely,xylose and xylo－ oligosaccharides, on the enzymatic selective hydrolysis of plant hemicelluloses,by the anaerobic culture of bifidobacterium adolescentis in vitro,and the abilit to promote the proliferation of bifidobacteria were examined.It was shown that the home－ made xylo－ oligosaccharides were cap able to support the growth of bifidobacterium adolescentis.It was found that the bifidobacterium adolescentis could metabolize xylobiose and xylotriose preferentially,and secrete extracellular enzymes,which were able to degrade the xylotetraose and xylopentose into the lower molecular weight xylo－ oligosaccharides to be digested easily by bifidobacterium adolescentis.

Key words: Xylo－ oligosaccharides Bifidobacterium adolescentis Anaerobic culture