The
presence of biologically active antimicrobial peptides
produced by the S. cerevisiae transformants
was indicated by agar diffusion assays against
sensitive indicator bacteria (e.g. Listeria monocytogenes
B73). The heterologous peptides were present
at relatively low levels in the yeast supernatant but
pediocin and leucocin activities were readily
detected when intact yeast colonies were used in
sensitive strain overlays. These preliminary results
indicate that it is indeed possible to develop
bactericidal wine yeast strains that could be useful
in the production of wine with reduced levels of
potentially harmful chemical preservatives.