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Evaluation of ITS PCR and RFLP for Differentiation and Identification of Brewing Yeast and Brewery ‘Wild’ Yeast Contaminants
Author(s) -
Pham T.,
Wimalasena T.,
Box W. G.,
Koivuranta K.,
Storgårds E,
Smart K. A.,
Gibson B. R.
Publication year - 2011
Publication title -
journal of the institute of brewing
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.523
H-Index - 51
eISSN - 2050-0416
pISSN - 0046-9750
DOI - 10.1002/j.2050-0416.2011.tb00504.x
Subject(s) - brewing , yeast , identification (biology) , restriction fragment length polymorphism , contamination , chemistry , biology , food science , polymerase chain reaction , biochemistry , botany , gene , fermentation , ecology
ABSTRACT A reference library of ITS PCR/RFLP profiles was collated and augmented to evaluate its potential for routine identification of domestic brewing yeast and known ‘wild’ yeast contaminants associated with wort, beer and brewing processes. This library contains information on band sizes generated by restriction digestion of the ribosomal RNA‐encoding DNA (rDNA) internal transcribed spacer (ITS) region consisting of the 5.8 rRNA gene and two flanking regions (ITS1 and ITS2) with the endonucleases Cfo I, Hae III, Hinf I and includes strains from 39 non‐ Saccharomyces yeast species as well as for brewing and non‐brewing strains of Saccharomyces . The efficacy of the technique was assessed by isolation of 59 wild yeasts from industrial fermentation vessels and conditioning tanks and by matching their ITS amplicon sizes and RFLP profiles with those of the constructed library. Five separate, non‐introduced yeast taxa were putatively identified. These included Pichia species, which were associated with conditioning tanks and Saccharomyces species isolated from fermentation vessels. Strains of the lager yeast S. pastorianus could be reliably identified as belonging to either the Saaz or Frohberg hybrid group by restriction digestion of the ITS amplicon with the enzyme Hae III. Frohberg group strains could be further sub‐grouped depending on restriction profiles generated with Hinf I.