Crude protein, which was obtained by the lysis of Protaminobacter ruber NR-1 with the addition of glycine to the culture in a middle logarithmic phase of the growth, contained a considerable amount of B_<12> and little nucleic acids. The supplement of the crude protein obtained from P. ruber -lysate shortened the fermentation period to some extent and fortified the B_<12> content that drastically decreased during the formation of fermented milk.
