Killer Yeasts And Their Application

A killer phenotype, associated with the production and secretion of killer toxins, is widespread among yeasts and in competitive conditions gives an advantage to killer yeast strains in relation to other, sensitive microorganisms colonizing the same ecological niche. Killer toxins are proteins, usually glycoproteins, that are able to kill strains of susceptible yeasts. Each killer toxin has unique properties that vary depending on the strain of yeast that produces it. These differences concern the location of genes that encode toxins, molecular weight, as well as mechanisms of action. Some strains of killer yeast are characterized by a wide range of antagonistic activity, inhibit the development of a number of yeast strains, as well as molds, and have been studied for many years in terms of their biotechnological potential. Killer yeast and its toxins can find potential application in many fields: in the production of food and beverages, especially during wine fermentation and maturation, in biological control of plant pathogens, in yeast biotyping and as new antifungal agents.

1. Introduction. 2. Biosynthesis and structure of killer toxins. 3. Properties of killer proteins. 4. The mechanism of action of killer toxins. 5. Use of killer yeasts and their toxins. 5.1. Application in viticulture. 5.2. Potential application in medicine. 5.3. Combating fungal diseases of plants. 5.4. Transgenic plants producing killer toxins. 5.5. Use of killer yeasts in the marine environment. 6. Summary