Comparison of quantitative analytical methods in evaluating acidophilic iron- and sulphur-oxidizing microorganisms liquid cultures.

Different quantitative methods to evaluate cell concentrations in acidophilic iron- and sulphur-oxidizing microorganisms liquid cultures have been compared with the "most probable number of viable germs" procedure. Plating and colony counting on recently developed solid media give good results when used with pure bacterial cultures, but plating efficiency decreases with natural mixed cultures.