ENZYMATIC ACTIVITIES INVOLVED IN GLYCEROL UTILIZATION BY Pediococcus pentosaceus FROM ARGENTINIAN WINE

PASTERIS, S.E.; STRASSER DE SAAD, A.M.

Microbiologie-Aliments-Nutrition

IEENA. International College Alexander Tessier. Châtenay-Malabry

Año: 1997 vol. 15 p. 139 - 145

0759-0644

The enzymatic activities involved in glycerol dissimilation by Pediococcus pentosaceus N5p growing on glycerol, glucose or both substrates were determined. The pathway of glycerol kinase and NAD-independent glycerol-3-phosphate dehydrogenase is present in this strain and stronger activities were detected in cell-free extracts from glycerol medium. The end products from glycerol were mainly D-lactate and acetate with low levels of aroma compounds. The enzymes related with lactate formation were NAD-dependent and NAD-independent lactated dehydrogenase, both at higher level in the cell-free extract from glucose medium. NAD-dependent L-LDH is activated by fructose 1,6-diphosphate and the level of D-LDH were always higher than that L-LDH whereas the opposite ratio in NAD-independent L-LDHs was observed. The results explained the absence or low levels of L-lactate obtained since the transformation of L-lactate to pyruvate is favored. Pyruvate  is droved by pyruvate dehydrogenase to acetaldehyde-TPP and from this compound acetate and aroma compounds were formed. The activities of á-acetolactate synthetase, diacetyl reductase, acetoin reductase were present at levels in agreement with aroma compounds production in the different media. The enzymes involved in acetate formation were acetate kinase and acetaldehyde dehydrogenase, the latter being present a very high level in the cell-free extracts from glycerol medium.