Abstract: The present application relates to a bacterial strain and a biologically active culture thereof, as well as the uses of said bacterial strain and said biologically active culture in food or feed-grade substance, food or feed composition and food or feed product.

Abstract: A recombinant plasmid useful as a cloning vector in lactic acid bacteria and only containing DNA of lactic acid bacterial origin, the plasmid comprising (a) a DNA fragment comprising a replication region functional in lactic acid bacteria and (b) a DNA fragment comprising a marker gene selectable in lactic bacteria, the expression of which allows one-step primary selection in lactic acid bacterial cells transformed with the recombinant plasmid; a method for constructing the cloning vector plasmid; the recombinant plasmid with an inserted gene coding for a desired gene product; a method of preparing an improved food starter culture by introducing the recombinant plasmid with an inserted gene coding for a desired gene product and food starter cultures prepared by the method are provided.

Abstract: DNA sequences, derived from Lactococcus lactis subsp. lactis, are useful as promoters and promoter/secretion promoting signals for heterologous or homologous expression in Gram-positive bacteria. In another aspect, the invention relates to vectors, such as plasmids, comprising the sequences of the present invention, and to host cells transformed with such vectors. Yet additional aspects of the present invention are related to methods for producing desired heterologous or homologous peptides or proteins employing the sequences, vectors, or transformed hosts of the invention. By means of the invention, greatly improved heterologous and homologous expression and secretion may be achieved in E. coli and in Gram-positive bacteria such as B. subtilis, Lactococcus and Lactobacillus.