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Medientyp:
E-Artikel
Titel:
Identification and Population Dynamics of Yeasts inSourdough Fermentation Processes by PCR-Denaturing GradientGelElectrophoresis
Beteiligte:
Meroth, Christiane B.;
Hammes, Walter P.;
Hertel, Christian
Erschienen:
American Society for Microbiology, 2003
Erschienen in:Applied and Environmental Microbiology
Sprache:
Englisch
DOI:
10.1128/aem.69.12.7453-7461.2003
ISSN:
0099-2240;
1098-5336
Entstehung:
Anmerkungen:
Beschreibung:
<jats:title>ABSTRACT</jats:title><jats:p>Four sourdoughs (A to D) were produced under practical conditions, using a starter obtained from a mixture of three commercially available sourdough starters and baker's yeast. The doughs were continuously propagated until the composition of the microbiota remained stable. A fungi-specific PCR-denaturing gradient gel electrophoresis (DGGE) system was established to monitor the development of the yeast biota. The analysis of the starter mixture revealed the presence of<jats:italic>Candida humilis</jats:italic>,<jats:italic>Debaryomyces hansenii</jats:italic>,<jats:italic>Saccharomyces cerevisiae</jats:italic>, and<jats:italic>Saccharomyces uvarum</jats:italic>. In sourdough A (traditional process with rye flour),<jats:italic>C. humilis</jats:italic>dominated under the prevailing fermentation conditions. In rye flour sourdoughs B and C, fermented at 30 and 40°C, respectively,<jats:italic>S. cerevisiae</jats:italic>became predominant in sourdough B, whereas in sourdough C the yeast counts decreased within a few propagation steps below the detection limit. In sourdough D, which corresponded to sourdough C in temperature but was produced with rye bran,<jats:italic>Candida krusei</jats:italic>became dominant. Isolates identified as<jats:italic>C. humilis</jats:italic>and<jats:italic>S. cerevisiae</jats:italic>were shown by randomly amplified polymorphic DNA-PCR analysis to originate from the commercial starters and the baker's yeast, respectively. The yeast species isolated from the sourdoughs were also detected by PCR-DGGE. However, in the gel, additional bands were visible. Because sequencing of these PCR fragments from the gel failed, cloning experiments with 28S rRNA amplicons obtained from rye flour were performed, which revealed<jats:italic>Cladosporium</jats:italic>sp.,<jats:italic>Saccharomyces servazii</jats:italic>,<jats:italic>S. uvarum</jats:italic>, an unculturable ascomycete,<jats:italic>Dekkera bruxellensis</jats:italic>,<jats:italic>Epicoccum nigrum</jats:italic>, and<jats:italic>S. cerevisiae.</jats:italic>The last four species were also detected in sourdoughs A, B, and C.</jats:p>