A new solid medium for isolating and enumerating Thiobacillus ferrooxidans.

The growth of seven Thiobacillus ferrooxidans strains was trested on various solid media prepared according to previously published procedures in comparison with a series of new formulations (TSMs, Thiobacillus solid media) set up in our laboratory. These media differed in the type of gelling agent and in the concentration of phosphate and ferrous ions. It was determined that the established formulations brought qualitatively and quantitatively unsatisfactory results whereas, among the new media, TSM 1 produced quantitative yields of T. ferrooxidans colonies. The TSM1 supports the growth of T. ferrooxidans strains and can be recommended for the estimation of cell numbers in liquid cultures and for the isolation of single clones. There was also a noticeable similarity in the morphology of colonies formed by different T. ferrooxidans strains.