Hybridization of Palm Wine Yeasts ( Saccharomyces Cerevisiae) with Brewers Yeast by Protoplast Fusion

Abstract

Haploid auxotrophic strains of Saccharomyces cerevisiae were selected from palm wine and propagated by protoplast fusion with Brewers yeast. Fusion resulted in an increase in both ethanol production and tolerance against exogenous ethanol. Mean fusion frequencies obtained for a mating types ranged between 8 x 10^-6 to 3.0 x 10^-5. Intraspecific fusion between yeast strains gave a higher fusion frequency than interspecific fusion. High efficiency fusion was obtained between a mating types with fusion frequency ranging between 1.4 x 10^-6 to 8.6 x 10^-4. The fusion hybrids were uninucleated and stable showing actual karyogamy and prototrophy within six months of storage. Percentage regeneration of protoplast to viable, vegetative cells was between 52% to 77%. Minimal back mutations (reversions) were observed.

Bio-Research Vol.1(1) 2003: 53-62



Key words: Protoplast fusion, palm wine Saccharomyces, ethanol