Bacterial Synthesis of Riboflavin in Man

Bacterial studies have shown B. coli communior to be predominant in 

16-24 hours incubation, the riboflavin content of the medium shows a corresponding and gradual decline. With continued incubation the count declines steadily and the riboflavin content shows a corresponding increase. The uninoculatcd broth control showed a drop during the first eight hours 

Najjar and Holt (155) studied the urinary excretion of the Fj compound on four subjects who ingested a diet of Crisco, Vitamin-free Casein (Sheffield) and Dextrimaltose no. 2 for a period of three months. The daily urinary output of F2 was equivalent to the excretion response after the intake of 20-30 mg. nicotinamide, although the daily intake of each subject amounted only to 1.5-2.0 mg. derived from the Dextrimaltose and the casein. When full doses of sulfasuxidine were given for a period of a month, none of the subjects showed a decrease in the F2 output. These results are indicative of synthesis of the vitamin although sulfasuxidine failed to inhibit the process. 

Oppel (148) produced quantitative evidence in respect to biotin. Human. subjects were found to excrete in the urine more biotin than they ingested in the diet. The stool output of biotin also was more than the amount ingested. Both urine and stools contained three to six times the biotin content of the diet. The conclusion was therefore drawn that bacterial synthesis was responsible. The results of Najjar and Holt (143) contain 

Vitamin Synthesis and Its Impucations in Hubian Nutrition 

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