OCCURRENCE OF ARGININE DEIMINASE PATHWAY ENZYMES IN ARGININE CATABOLISM BY WINE LACTIC-ACID BACTERIA

L-Arginine, an amino acid found in significant quantities in grape jui ce and wine, is known to be catabolized by some wine lactic acid bacte ria. The correlation between the occurrence of arginine deiminase path way enzymes and the ability to catabolize arginine was examined in thi s study. The activities of the three arginine deiminase pathway enzyme s, arginine deiminase, ornithine transcarbamylase, and carbamate kinas e, were measured in cell extracts of 35 strains of wine lactic acid ba cteria. These enzymes were present in all heterofermentative lactobaci lli and most leuconostocs but were absent in all the homofermentative lactobacilli and pediococci examined. There was a good correlation amo ng arginine degradation, formation of ammonia and citrulline, and the occurrence of arginine deiminase pathway enzymes. Urea was not detecte d during arginine degradation, suggesting that the catabolism of argin ine did not proceed via the arginase-catalyzed reaction, as has been s uggested in some earlier studies. Detection of ammonia with Nessler's reagent was shown to be a simple, rapid test to assess the ability of wine lactic acid bacteria to degrade arginine, although in media conta ining relatively high concentrations (>0.5%) of fructose, ammonia form ation is inhibited.