PHENOLIC ACIDS AND IRON TRANSPORT IN BACILLUS SUBTILIS

The capacity of Bacillus subtilis for iron uptake was increased about 20-fold by growing the cells in an iron-deficient medium. Omission of citrate from the medium increased this capacity a further 4-fold. Iron uptake involved two steps: (1) binding of iron to the cell, which was temperature- and energy-independent, and (2) active transport of iron. The addition of low levels of phenolic acids to iron-deficient medium increased both the rate and extent of iron uptake. Mutants unable to synthesize normal levels of phenolic acid were shown to have a reduced capacity for iron uptake after growth in an iron-deficient medium. © 1968.