Distribution of Diacetyl Reductase among Bacteria

Abstract

Rapid loss of diacetyl in mixed strain lactic streptococcus starter cultures was due to enzymatic reduction of diacetyl to acetoin by diacetyl reductase. It was irreversible and required DPNH for activity. Selecting strains containing no diacetyl reductase is important for compounding flavorful mixed strain starter cultures. Consequence of contamination of dairy products by diacetyl reductase-containing bacteria is emphasized. Possible uses of enzyme for diacetyl determination and removal of diacetyl from fermented beverages and citrus juices are indicated.