Construction of a hybrid brewing strain of saccharomyces carlsbergensis by mating of meiotic segregants

Abstract

A brewing strain of Saccharomyces carlsbergensis yielded upon sporulation 1-, 2- and 3-spored asci. The spore viability was low, but a number of clones could be derived from the spores. Among these a- and α-maters were identified revealing that the parental brewing strain is heterozygous for the two mating type alleles. A number of lines with opposite mating type were crossed pairwise. One of the hybrids produced by mating of two presumably haploid or near haploid clones was equal to the parental strain in brewing performance on a pilot scale. The separation of the nuclear genomes of brewer's yeast into individual cells and their successful mating into hybrid strains opens the possibility to introduce genetic alterations in brewing strains by mutagenesis and genetic transformation of the haploid lines. © 1981 Carlsberg Laboratory.