Humicola sp., a thermophilic fungus, was used for the production of extracellular a-galactosidase on various agricultural residues in solid-state fermentation (SSF). Maximum enzyme activity (44.6 U/g of original substrate) was produced when soya flour was used as carbon source at 45 degrees C. The enzyme produced hydrolyzed raffinose and stachyose from soymilk within 2 h at 50 degrees C. Scanning electron microscopic (SEM) studies showed a high density growth of fungal mycelia on wheat bran particles during solid-state fermentation.