A color-variant strain of Aureobasidium pullulans (NRRL Y-12974) produced alpha-L-arabinofuranosidase (alpha-L-AFase) when grown in liquid culture on sugar beet arabinan, wheat arabino-xylan, L-arabinose, L-arabitol, xylose, xylitol, oat spelt xylan, corn fiber, or arabinogalactan. L-Arabinose was most effective for production of both whole-broth and extracellular alpha-L-AFase activity, followed by L-arabitol. Oat spelt xylan, sugar beet arabinan, xylose, xylitol, and wheat arabinoxylan were intermediate in their ability to support alpha-L-AFase production. Lower amounts of enzyme activity were detected in corn fiber- and arabinogalactan-grown cultures.