The Influence of Pichia Killer Toxins on the Wine Spoilage Yeasts
نویسندگان
چکیده
Killer yeasts are able to produce toxins that antagonize the growth of susceptible yeasts cells of the same species or the ones that are related to them. Killer strains are resistant to their own toxins but can be sensitive to killer proteins of other yeasts. The killer proteins of Pichia spp. are known for its broad spectrum of antifungal activity including pathogens such as Candida albicans. The aim of the study was to investigate the potential of the partly purified killer toxins to inhibit the growth of selected yeast strains which can contribute to wine spoilage. Three Pichia killer yeast strains (CBS 1982, CBS 5759, CBS 7373) were used in the study. The killer protein secreted by Pichia anomala CBS 1982 was characterized by the highest antifungal activity. The most pronounced effect of the reduction of cell proliferation by killer toxin preparations was found after 2 and 20 h cultivation. Among the 13 tested strains, all Pichia killer toxin preparations inhibited the growth of Rhodotorula graminis Rg, Rhodotorula mucilaginosa Rm and Schizosaccharomyces pombe DSM 70576. Killer toxins produced by Pichia anomala CBS 1982 (K8) and CBS 5759 (K4) limited the growth of Candida pulcherrima K5 and Hanseniaspora guillermondii DSM 3432 after 2, 20 and 168 h of incubation. A significant reduction of Debaryomyces hansenii DSM 3428 biomass was observed in medium with the addition of one toxin preparation (Pichia anomala CBS 1982). The growth limitation of Candida glabrata DSM 6425, Hanseniaspora uvarum DSM 2768, Metchnikowia pulcherrima DSM 70321 and Cryptococcus laurentii DSM 70766 was noticed only after 2 hours cultivation in presence of killer protein preparations. The killer toxins could be used in the food industry as selective tools to control infections during the fermentation of wine and improve the quality of the final product.
منابع مشابه
Pichia anomala and Kluyveromyces wickerhamii killer toxins as new tools against Dekkera/Brettanomyces spoilage yeasts.
Two yeast killer toxins active on spoilage yeasts belonging to the genus Dekkera/Brettanomyces are here described for the first time. The two toxins produced by Pichia anomala (DBVPG 3003) and Kluyveromyces wickerhamii (DBVPG 6077), and named Pikt and Kwkt, respectively, differ for molecular weight and biochemical properties. Interestingly, the fungicidal effect exerted by Pikt and Kwkt against...
متن کاملSpoilage yeasts in Patagonian winemaking: molecular and physiological features of Pichia guilliermondii indigenous isolates.
Yeasts belonging to the genus Dekkera/Brettanomyces, especially the species Dekkera bruxellensis, have long been associated with the production of volatile phenols responsible for off-flavour in wines. According to recent reports, the species Pichia guilliermondii could also produce these compounds at the initial stages of fermentation. Based on the abundance of P. guilliermondii in Patagonian ...
متن کاملPMKT2, a new killer toxin from Pichia membranifaciens, and its promising biotechnological properties for control of the spoilage yeast Brettanomyces bruxellensis.
Pichia membranifaciens CYC 1086 secretes a killer toxin (PMKT2) that is inhibitory to a variety of spoilage yeasts and fungi of agronomical interest. The killer toxin in the culture supernatant was concentrated by ultrafiltration and purified to homogeneity by two successive steps, including native electrophoresis and HPLC gel filtration. Biochemical characterization of the toxin showed it to b...
متن کاملThe Biology of Pichia membranifaciens Killer Toxins
The killer phenomenon is defined as the ability of some yeast to secrete toxins that are lethal to other sensitive yeasts and filamentous fungi. Since the discovery of strains of Saccharomyces cerevisiae capable of secreting killer toxins, much information has been gained regarding killer toxins and this fact has substantially contributed knowledge on fundamental aspects of cell biology and yea...
متن کاملOptimization of killer assays for yeast selection protocols.
A new optimized semiquantitative yeast killer assay is reported for the first time. The killer activity of 36 yeast isolates belonging to three species, namely, Metschnikowia pulcherrima, Wickerhamomyces anomala and Torulaspora delbrueckii, was tested with a view to potentially using these yeasts as biocontrol agents against the wine spoilage species Pichia guilliermondii and Pichia membranifac...
متن کامل