) Glycerol catabolism was studied in Pediococcus pentosaceus N 5 p isolated from wine, growing on different glycerol concentrations in aerobic conditions. The highest levels of the activities of this pathway were expressed at the lowest concentration of glycerol, decreasing with the increase in glycerol concentration in the growth media. Glycerol was transformed in d -lactate, acetate, diacetyl and 2,3-butanediol. Diacetyl reductase and acetoin reductase were inhibited by glycerol, whereas NAD-independent lactate dehydrogenases, NADH oxidase as CoA-independent acetaldehyde dehydrogenase, and acetate kinase were stimulated. The behavior of the enzymatic activities was in conformity with the fermentation balances;