Yeast species composition differs between artisan bakery and spontaneous laboratory sourdoughs

Authors

  • Gino Vrancken,

    1. Research Group of Industrial Microbiology and Food Biotechnology, Faculty of Sciences and Bio-engineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium
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  • Luc De Vuyst,

    1. Research Group of Industrial Microbiology and Food Biotechnology, Faculty of Sciences and Bio-engineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium
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  • Roel Van der Meulen,

    1. Research Group of Industrial Microbiology and Food Biotechnology, Faculty of Sciences and Bio-engineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium
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  • Geert Huys,

    1. Laboratory for Microbiology, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
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  • Peter Vandamme,

    1. Laboratory for Microbiology, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
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  • Heide-Marie Daniel

    1. Mycothèque de l'Université catholique de Louvain (MUCL), Member of the Belgian Coordinated Collection of Microorganisms (BCCM), Earth and Life Institute, Mycology, Université catholique de Louvain, Louvain-la-Neuve, Belgium
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  • Editor: Cletus Kurtzman

Correspondence: Heide-Marie Daniel, BCCM/MUCL, Earth and Life Institute, Mycology, Université catholique de Louvain, Croix du Sud 3, bte 6, B-1348 Louvain-la-Neuve, Belgium. Tel.: +32 10 473 956; fax: +32 10 451 501; e-mail: heide-marie.daniel@uclouvain.be

Abstract

Sourdough fermentations are characterized by the combined activity of lactic acid bacteria and yeasts. An investigation of the microbial composition of 21 artisan sourdoughs from 11 different Belgian bakeries yielded 127 yeast isolates. Also, 12 spontaneous 10-day laboratory sourdough fermentations with daily backslopping were performed with rye, wheat, and spelt flour, resulting in the isolation of 217 yeast colonies. The isolates were grouped according to PCR-fingerprints obtained with the primer M13. Representative isolates of each M13 fingerprint group were identified using the D1/D2 region of the large subunit rRNA gene, internal transcribed spacer sequences, and partial actin gene sequences, leading to the detection of six species. The dominant species in the bakery sourdoughs were Saccharomyces cerevisiae and Wickerhamomyces anomalus (formerly Pichia anomala), while the dominant species in the laboratory sourdough fermentations were W. anomalus and Candida glabrata. The presence of S. cerevisiae in the bakery sourdoughs might be due to contamination of the bakery environment with commercial bakers yeast, while the yeasts in the laboratory sourdoughs, which were carried out under aseptic conditions with flour as the only nonsterile component, could only have come from the flour used.

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