A protoplast electrofusion was carried out between two industrial wine-making strains: Saccharomyces cerevisiae S.o./2 and S. cerevisiae rho– ATCC 38637; the latter one is used to regulate acidity in grape wines after the completed alcoholic fermentation. For the purpose of selecting markers, which enable the isolation of fusants, there was determined the ability of the two strains to assimilate different types of carbon sources, as well as the their ability to grow on a medium with an increased content of saccharose and cycloheximide. Prior to starting the electrofusion process, the protoplastisation was enhanced by applying changing amounts and combinations of various types of lytical enzymes. Also, optimal parameters of the electrofusion process were determined. From a group of fusants, two stable hybrids (F1 and F2) were selected and described in order to determine the following parameters: DNA content in a cell, their ability to convert malic acid into lactic acid, and their potential to produce ethanol. The results obtained prove that the two strains investigated contain an increased content of DNA in cells. The yield of a malolactic fermentation as provided by the fusants was comparable to the yield of malolactic fermentation run by the strain S. cerevisiae rho– ATCC 38637, and the yield of the alcoholic fermentation run by these fusants was comparable to the alcoholic fermentation yield provided by the strain S.cerevisiae S.o./2.
protoplast electrofusion, malolactic fermentation, Saccharomyces cerevisiae