Sulfur compound production by Geotrichum candidum from L-methionine:: importance of the transamination step

L-Methionine degradation products and catabolic enzymatic activities involved in methanethiol generation were investigated in Geotrichum candidum GcG. L-Methionine was easily degraded by G. candidum and the transammation product.. 4-methylthio-2-oxobutyric acid (KMBA), was found to transiently accumulate. In parallel, considerable L-methionine aminotransferase activity was found in this microorganism. L-Methionine and KMBA demethiolating activities were also detected. The degradation of KMBA corresponded to an overall increase in the production of volatile sulfur compounds. These results show that the transamination pathway is of major importance in the initial breakdown of L-Methionine by this cheese-ripening microorganism. (C) 2001 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.