GROWTH OF CHLAMYDOMONAS MUNDANA IN THE PRESENCE OF DIFFERENT SYNTHETIC CHELATORS.

Six synthetic chelators were investigated in culture media for Chlamydomonas mundana. The effects on growth of chelator-iron ratios in the range 25 to 400 muM were studied in relation to Ca, heavy metal concentrations, and incubation time. Effects ranged from none through stimulation to inhibition. The most delicate balance of trace metal requirements with any given chelator was established by growth determinations. The behavior of chelators as they affect trace metals in culture media was best understood by consideration of absolute as well as relative stabilities of their metal chelates. Although all the chelators tested, when properly supplemented with microelements, allowed excellent growth, diethylenetriaminepentaacetic acid and diaminocyclohexanetetraacetic acid were least affected by additions of heavy metals and are recommended for use at 50 to 100 muM.