抄録
Investigations were made on all the processes of preparing riboflavin from the cultured broth containing cane molasses and fish meal as main substrates, and the following results were obtained : 1) By separation of solids from the broth, a crude riboflavin solution containing 91% of riboflavin was obtained. 2) Less than 5 % of riboflavin was lost by the deproteinization with 1 % of alum added to a solution containing 100 mg % or less of riboflavin. 3) Reduced riboflavin was obtained in the yield of 93 % by the addition of sodium hydrosulfite, three times as much as riboflavin contained in the solution. 4) After oxidation of reduced riboflavin precipitate, riboflavin was recrystallized and obtained in the yield of 80 %. This yield corresponded approximately to 70 % of riboflavin contained in the initial solution.
