Differentiation of contaminating yeasts in brewery by PCR-based techniques

Restriction fragment length polymorphism (RFLP) patterns of PCR-amplified ribosomal RNA gene fragments (rDNA) and randomly amplified polymorphic DNA (RAPD) were applied to the analysis of 19 yeast strains isolated in Polish breweries from pitching yeast, fermenting wort and final beer. One five-base (ScrFI) and two four-base cutting (HaeIII, MspI) restriction enzymes were used. Primer 21 (5′-GCTCGTCGCT-3′) was selected for RAPD analysis. Among the isolates tested, high molecular diversity in the length of electrophoretically separated products was observed. The results show that it is possible to differentiate between brewing yeast and wild yeast isolates by their electrophoretic patterns.