Enrichment and Isolation Procedures

The methods are the same as those described for the genus Chromatium. Thiocapsa roseopersicina is one of the most common purple sulfur bacteria in nature. It is particularly abundant in ponds, pools, or lagoons receiving sewage or wastewater rich in organic matter. Since this species is the least fastidious purple sulfur bacterium known, its isolation presents no problems. The other species of Thiocapsa, Thiocapsa pendens and Thiocapsa rosea, can be isolated directly from samples collected in nature by agar shake dilution cultures, as described for the Chromatium species.

The color of colonies in agar is characteristically pinkish. Because of their gas vesicle content, colonies of Thiocapsa pendens and Thiocapsa rosea maintain a chalky appearance, even if the cells are free of S0.

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