Biological effect of extracellular peptide factor from Luteococcus japonicus subsp. casei on probiotic bacteria

Abstract

The biological effect of the extracellular peptide reactivating factor (RF) from Luteococcus casei on cells of probiotic cultures was studied. The RF showed the protective and reactivating effects on the Bifi dobacterium bifidum cells under the action of bile salts and an acidic stress. Also, it acted as a cryoprotector during lyophilisation and long term culture storage. The RF and the L. casei culture liquid (CL) were shown to have bifidogenic properties. The degree of protection and reactivation of lactic acid bacteria under the action of bile salts depended on the particular strain properties. The maximum degree of protection (more than thirteen fold) and reactivation (close to three fold) was found in Lactobacillus casei, while the minimum values were characteristic of Lactobacillus reuterii. The resistance of lactobacilli to bile was increased in the row of L. acidophilus, L. casei, L. plantarum, L. rhamnosus, and L. reuterii correlating with the RF protection degree.