Aspects of iron metabolism in Bifidobacterium bifidum var. pennsylvanicus

1. 1. Btfidobacterium bifidum var. Pennsylvanias requires ferrous iron for growth, and cannot utilize ferric iron even in the presence of siderophores. 2. 2. Acid production by the microorganisms is dependent in part on iron content of the medium. 3. 3. Heme and heme-containing proteins inhibit the microbial growth, and it is proposed that this is in part responsible for the change in the infant's intestinal flora upon weaning. 4. 4. Bacterial growth inhibition brought about by heme cannot be restored by heme biosynthesis intermediates, and known heme biosynthesis inhibitors have no effect on bacterial growth. The basis for heme-induced microbial growth inhibition remains unclear.