Bread yeast strains

A method for obtaining a broad spectrum strain of Saccharomyces cerevisiae, comprising the steps of:

• selecting a strain of Saccharomyces cerevisiae having:
• an invertase activity of 300 units or more;
• a maltase activity of less than 80 units;
• and
• a fermentative capacity of 110 mL or more in an unsweetened dough;
• and
• inactivating m copies of a SUC gene of said selected strain by disruption, m being a whole number equal to 10, 11 or 12, such that the invertase activity of the selected and inactivated strain is 20 units or less, wherein the inactivation step comprises:
• a step a) of transforming said selected strain with a disruption cassette comprising a selection marker flanked by two lox sequences, said lox sequences being flanked by two homologous recombination sequences, wherein each of said two homologous recombination sequences comprises a fragment of SEQ ID NO:
• 3;
• a step b) of selecting transformed strains that have integrated the disruption cassette;
• and
• an optional step c) of eliminating the selection marker,
• wherein the ratio between invertase and maltase is altered from at least 5:1 before inactivation to at least 1:5 after inactivation of the m copies of SUC genes in the Saccharomyces cerevisiae strain.