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: A continuous process for the preparation of immobilized glucoamylase useful for the long term continuous direct hydrolysis of starch to fermentable glucose at temperatures of 45.degree. or higher is carried out by continuously depositing and stabilizing glucoamylase on a porous, particulate, macroreticular anionic ion exchange resin having a high osmotic shock resistance value. Processes for detoxifying, stripping and regenerating the biocatalyst are also disclosed.