Byssochlamys fulva CMI 40021 produced an alpha-amylase and low levels of an amyloglucosidase extracellularly. The purified alpha-amylase catalyzed the conversion of starch to maltose (55%, w/w) as the predominant end product. It would appear that the high levels of maltose produced by the B. fulva alpha-amylase are not due to direct hydrolysis but can be attributed to transglycosylation reactions using short chain saccharides that accumulate during the early stages of starch hydrolysis. In particular maltotriose and maltotetraose readily undergo transglycosylation reactions at high substrate concentrations. The products of these reactions are subsequently hydrolyzed to give high levels of maltose.