1. A recombinant vector for expressing and secreting, by a propionibacterium , at least one eukaryotic peptide of interest or eukaryotic protein of interest, comprising at least: under the control of at least one suitable promoter, i) at least one nucleic acid sequence encoding a propionibacterial signal peptide, which is the sequence of the surface layer protein of a P. freudenreichii and, ii) at least one nucleic acid sequence encoding said eukaryotic peptide of interest or eukaryotic protein of interest; wherein said at least one nucleic acid sequence encoding a propionibacterial signal peptide is translationally fused to said at least one nucleic acid sequence encoding said eukaryotic peptide of interest or eukaryotic protein of interest, wherein said nucleic acid sequence encoding a propionibacterial signal peptide, which is the sequence of the surface layer protein of a P. freudenreichii , is selected from the group consisting of: the sequences SEQ ID NOs: 59 to 68.