RAFFINOSE-HYDROLYZING ACTIVITY OF ASPERGILLUS-FUMIGATUS

Aspergillus fumigatus can utilize raffinose and melibiose as its sole carbon source. Substantial extracellular raffinolytic and invertase ac tivities were produced during fungal growth on raffinose. These activi ties were induced also by sucrose, melibiose and wheat straw but not b y 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 th e culture filtrate. The crude enzyme retained about 80% of the origina l activity (2 U/mL) after incubation for 2 h at 50 degrees C.