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Candida pyralidae killer toxin disrupts the cell wall of Brettanomyces bruxellensis in red grape juice
Author(s) -
Mehlomakulu N.N.,
Prior K.J.,
Setati M.E.,
Divol B.
Publication year - 2017
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/jam.13383
Subject(s) - food spoilage , biology , yeast , pyralidae , propidium iodide , population , wine , food science , microbiology and biotechnology , biochemistry , botany , bacteria , programmed cell death , apoptosis , lepidoptera genitalia , genetics , demography , sociology
Aims The control of the wine spoilage yeast Brettanomyces bruxellensis using biological methods such as killer toxins (instead of the traditional chemical methods, e.g. SO 2 ) has been the focus of several studies within the last decade. Our previous research demonstrated that the killer toxins Cp KT 1 and Cp KT 2 isolated from the wine yeast Candida pyralidae were active and stable under winemaking conditions. In this study, we report the possible mode of action of Cp KT 1 on B. bruxellensis cells in red grape juice. Methods and Results Brettanomyces bruxellensis cells were exposed to Cp KT 1 either directly or through co‐inoculation with C. pyralidae . This exposure yielded a temporary or permanent decline of the spoilage yeast population depending on the initial cell concentration. Scanning electron microscopy revealed cell surface abrasion while propidium iodide viability staining showed that Cp KT 1 caused plasma membrane damage on B. bruxellensis cells. Our data show that the exposure to Cp KT 1 resulted in increased levels of β ‐glucan, suggesting a compensatory response of the sensitive cells. Conclusions The toxin Cp KT 1 causes cell membrane and cell wall damage in B. bruxellensis . Significance and Impact of the Study Candida pyralidae shows potential to be used as a biocontrol agent against B. bruxellensis in grape juice/wine.