Genetics of Proteolytic Enzymes of Lactococci and Their Role in Cheese Flavor Development

In recent years, knowledge of the genetics and biochemistry of the enzymes that constitute the proteolytic system of starter lactococci has increased tremendously. This paper summarizes the data obtained largely in the last 5 yr of intensive research by various research groups operative in this field. The emphasis is on proteinase and peptidase enzymes and their genes and on the manipulation of proteolytic capacity of the bacteria by genetic techniques. The prospect of such genetically engineered strains in cheese fermentation and the first results in this area are discussed.