Application of polymerase chain reaction to determine the flocculation properties of brewer's lager yeast

We developed a polymerase chain reaction method to determine the flocculati on ability of yeast based on one of the flocculation genes. More than 30 br ewer's lager yeast strains were examined, and the amplification of the targ eted flocculation gene was confirmed in all of the flocculating yeast strai ns. The method was also successfully applied to the early detection of nonf locculating mutants by examining yeast cells individually. In some applicat ions, we were able to determine the cause genetically when yeast suddenly d id not flocculate and failed to sediment toward the end of fermentation. Th is method not only yields rapid results but also offers reliability and rep roducibility.