Autolysis detection and evaluation of some lactic acid bacteria by renaturing sodium dodecyl sulphate‐polyacrylamide gel electrophoresis and polymerase chain reaction assays

Eleven lactic acid bacterial strains were tested for autolysis ability and the presence of autolytic enzymes by renaturing sodium dodecyl sulphate‐polyacrylamide gel electrophoresis ( SDS ‐ PAGE ). Polymerase chain reaction ( PCR ) assays for the detection of lysogenic strains were performed. Autolysis in a buffer system was observed in L actobacillus delbrueckii subsp. bulgaricus DSM 20080 , L. delbrueckii subsp. bulgaricus DSM 20081 , B ifidobacterium longum subsp . infantis DSM 20088 , B. angulatum DSM 20098 and S treptococcus thermophillus DSM 20617. Mitomycin C induction of prophage was demonstrated in B. longum subsp. infantis DSM 20088 , B. angulatum DSM 20098, L actobacillus acidophilus DSM 20242 and S. thermophillus DSM 20617. The presence of genes encoding known bacteriophage lysins was demonstrated by a PCR assay and correlated well with the autolytic phenotypes of the strains, indicating that PCR screening is useful in the rapid identification of autolytic strains.