Arabinoxylan ('Cellace') corn fiber, containing 28.1% (w/w) as L-arabinose and 32.8% (w/w) as D-xylose, was hydrolyzed by a crude enzyme containing beta -xylanase, beta -xylosidase and alpha -L-arabinofuranosidase originating from the extracellular culture broth of Penicillium funiculosum. The resultant hydrolysate contained L-arabinose, D-xylose and small amounts of other mono- and oligosaccharides. The L-arabinose and D-xylose were 21.3% (w/w) and 18.7% (w/w), respectively, based on the initial arabinoxylan. Williopsis saturnus var. saturnus, which metabolizes D-xylose without using L-arabinose, was aerobically cultured in the hydrolysate at 30 degreesC for 96 h. The sugar solution after removal of yeast cells contained L-arabinose and D-xylose which were 20.3% (w/w) and 0.002% (w/w), respectively, of the initial arabinoxylan. The solution was decolorized with activated carbon, and deionized with cation-and anion-exchange resins. The clear sugar solution thus obtained was composed of L-arabinose and D-xylose which were 19.3% (w/w) and 0.001% (w/w), respectively, of the initial arabinoxylan. After concentration of the sugar solution under reduced pressure, followed by crystallization of L-arabinose, 16% (w/w) L-arabinose (based on the initial arabinoxylan) was obtained as crude crystals. No D-xylose was detected in the final preparation.