Abstract
The growth of Escherichia coli was inhibited by ethylene glycol bis(beta-aminoethyl ether)-N,N,N′,N′-tetraacetic acid (EGTA) in a medium of initial pH 8.8. The growth inhibition was reversed by the addition of CaCl2. E. coli could grow in the presence of EGTA at pH values below 8. The concentration of free calcium ions increases with a decrease in medium pH because of a decrease in the calcium binding capacity of EGTA. So, although the results suggest that calcium ions are essential for the growth of E. coli, the minimum concentration required is very low.
