Acid Bacteria Metabolism and its Impact on Wine Quality

Lactic Acid Bacteria Metabolism and its Impact on Wine Quality (Table 15.2) 

L-malic acid is decarboxylated to L-lactic acid by LAB, a reaction known as MLF. Wine pH increases by several tenths of units depending on the initial malic acid concentration, which may range from 1 to 8 g/1. Although the MLF reaction has been known for a long time (Seifert 1901) only since the 1970s has the malolactic enzyme been purified and characterized, first from Lact. plcmtarum 

Substrates Pathways/first enzyme Products Conditions Impact on the quality 

Carbohydrates Glucose Heterofermentation Acetic acid Usual conditions of winemaking Low 

Fructose Stuck alcoholic fermentation High volatile acidity (piqure lactique) 

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