Aspergillus fumigatus can utilize raffinose and melibiose as its sole carbon source. Substantial extracellular raffinolytic and invertase activities were produced during fungal growth on raffinose. These activities were induced also by sucrose, melibiose and wheat straw but not by glucose. Hydrolysis of both raffinose and sucrose was optimal at pH 4.5 to 5.5 and 55 to 60 degrees C. Melibiose was also hydrolyzed by the culture filtrate. The crude enzyme retained about 80% of the original activity (2 U/mL) after incubation for 2 h at 50 degrees C.