Abstract: A concentrated bacterial culture, capable of being cooled to temperatures as low as about -40.degree. C. for storage without rapid freezing and with minimum damage to the bacterial cells, is prepared by diluting a conventionally prepared concentrated cell paste with a liquid anti-freeze agent containing one or more water freezing point depressants which are water-soluble, are non-injurious to the bacteria, and do not form crystals when cooled to a predetermined temperature within the range of about 5 to about -40.degree. C. The amount of the freezing point depressant(s) is sufficient to prevent formation of ice crystals from the water present in the diluted product when cooled to the predetermined temperature. The culture, which does not become hard or crystalline upon being cooled to temperatures as low as -40.degree. C., can be warmed to a temperature convenient for sampling, assaying and blending and then re-cooled to a cold storage temperature without an appreciable reduction in viability.

Abstract: An insolubilized antibody suitable for an enzyme immuno assay or radio immuno assay, which has characteristic infrared absorptions at around 1,040 cm.sup.-1, 1,540 cm.sup.-1 and 1,640 cm.sup.-1 and is prepared by chemically binding an antibody to cell wall debris of bacteria or yeasts whose shape is globular or rod-like. There is further disclosed an enzyme immuno assay or radio immuno assay using the insolubilized antibody and a kit containing the insolubilized antibody.

Abstract: An improved process for producing .alpha.-glycerophosphate oxidase provides yields of more than 1500 U per liter. The enzyme is produced by growing a member of the family Lactobacillaceae in a medium comprising pyruvate and an inducer for .alpha.-glycerophosphate oxidase. In the preferred embodiment, a medium comprising a mixture of glucose and pyruvate as carbon sources provides a synergistic effect on the production of .alpha.-glycerophosphate oxidase.