Growth and Maintenance of Thiobacillus ferrooxidans Cells.

A rapid and sensitive spectrophotometric procedure was developed for monitoring the growth of Thiobacillus ferrooxidans in liquid culture. Values determined for the optical densities at 500 nm of washed T. ferrooxidans cell suspensions were directly proportional to both total cell number and total cell protein concentration and provided an accurate measurement of culture growth rate. The utility of this procedure was demonstrated by conducting physiological studies on the influence of CO(2) and FeSO(4) availability on the growth of T. ferrooxidans. In addition, we describe a procedure for the long-term maintenance of cells T. ferrooxidans that ensures culture purity and genetic stability.