Abstract: Phaffia rhodozyma strains are described which produce greater than 3,000 ppm astaxanthin based on dry yeast solids when cultivated in a volume of nutrient medium of at least about 1,500 liters and containing in excess of 4 percent, preferably in excess of 6 percent, dry yeast solids. These and other strains are cultivated by an improved fermentation method comprising extending the maturation phase of the fermentation by one or more various techniques including exposing the yeast cells to a low-intensity light, slow feeding the cells with a rapidly metabolized energy source, e.g. glucose, and replacing the rapidly metabolized energy source with a slowly metabolized energy source, e.g. gylcerol. The cells of these strains are incorporated into animal feeds, particularly feeds for salmonid fishes, to impart or enhance the red pigmentation of these animals and products made from these animals.

Abstract: Phaffia rhodozyma strains are described which produce greater than 3,000 ppm astaxanthin based on dry yeast solids when cultivated in a volume of nutrient medium of at least about 1,500 liters and containing in excess of 4 percent, preferably in excess of 6 percent, dry yeast solids. These and other strains are cultivated by an improved fermentation method comprising extending the maturation phase of the fermentation by one or more various techniques including exposing the yeast cells to a low-intensity light, slow feeding the cells with a rapidly metabolized energy source, e.g. glucose, and replacing the rapidly metabolized energy source with a slowly metabolized energy source, e.g. gylcerol. The cells of these strains are incorporated into animal feeds, particularly feeds for salmonid fishes, to impart or enhance the red pigmentation of these animals and products made from these animals.

Abstract: Novel biologically pure quick acting bakers yeast strains ATCC 20784, ATCC 20785, and ATCC 20786 are provided which show good performance in sweet, regular, and lean doughs, and superior performance in sweet and lean dough, particularly when used in the active dry yeast form. A method of obtaining these and other novel bakers yeast strains by hybridization via protoplast fusion of petite mitochondrial mutants is also provided. Improved methods of baking using these novel bakers yeasts especially in the active dry yeast form are also provided.

Abstract: Novel biologically pure quick acting bakers yeast strains NRRL Y-15338 and NRRL Y-15339 are provided which show good performance in sweet, regular, and lean doughs, and superior performance in sweet and lean doughs, particularly when used in the active dry yeast form. A method of obtaining these and other novel bakers yeast strains by hybridization via protoplast fusion of petite mutants is also provided. Improved methods of baking using these novel bakers yeasts especially in the active dry yeast form are also provided.