Enrichment and Isolation Procedures

Media and culture conditions are the same as described for Chro-matium species. Allochromatium vinosum is one of the most com mon purple sulfur bacteria in nature. Since it is a nonfastidious purple sulfur bacterium, it can be readily isolated. Allochromatium vinosum is enriched at high sulfide concentrations (3-4 mM), at high light intensities of more than 1000 lux and at incubation temperatures of 20-30°C. This species is among the dominant members of the Chromatiaceae in enrichment cultures under strictly autotrophic conditions, but also in the presence of organic substrates and complex nutrients, if present in the sample. Allochromatium species can also be isolated directly by agar shake dilution cultures from samples collected in nature, as described for Chromatium species.

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