Utilization of amino acids and peptides and peptidase activities in proteinase-negative Lactococcus lactis FH 041

The ability of the proteinase-negative Lactococcus lactis FH 041 to utilize amino acids and peptides, and its peptidase activities were examined. Stra in FH 041 and its parent strain UC 317 exhibited similar growth rates in a medium with casein hydrolysate as the sole nitrogen source. Growth of strai n FH041 in media containing different amino acids, each as the sole nitroge n source, indicated a preference for hydrophilic over hydrophobic amino aci ds. It also preferentially utilized cheese peptides of less than 2 kDa. Str ain FH041 exhibited strictly intracellular general aminopoeptidase and X-pr opyldipeptidyl aminopeptidase activities, and most of its endopeptidase and dipeptidase activities were also intracellular.