Some observations on the utilization of organic compounds by purple sulphur bacteria

Summary

Enrichment cultures of purple sulphur bacteria from Delft mud were made in inorganic media. By means of shake-cultures in agar with inorganic salts it was attempted to isolate a strain, the growth of which was not favoured by organic substances. This aim could not be attained as all strains isolated throve better in media containing sodium malate than in completely inorganic ones. So it may be concluded that purple sulphur bacteria, at least those isolated from ordinary mud, show a better development under photo-heterotrophic than under photo-autotrophic conditions.