Sulfur compound production by Geotrichum candidumfrom l‐methionine: importance of the transamination step

l‐Methionine degradation products and catabolic enzymatic activities involved in methanethiol generation were investigated in Geotrichum candidumGcG. l‐Methionine was easily degraded by G. candidumand the transamination 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.