Question

Based on the following table of characteristics for each group, what would be the surest way to enrich purple nonsulfur bacteria from an environmental sample? Bacterial Group use organic C Fix N2 Fix CO2 e donors Purple sulfur no no yes H2S Purple nonsulfur yes yes some do H, H,S, Fe2+ Green sulfur no yes H2S Green nonsulfur yes no some do H2S, H2 no O Providing mineral salts, organic carbon and light, but excluding fixed nitrogen and filling the gaseous headspace with N2. O Providing mineral salts, CO2, light and H2S but no organic carbon. O Providing mineral salts, CO2 and light, but no organic carbon. O Providing mineral salts, organic carbon, light and H2, but no CO2.

Answer 1

The surest way to enrich purple non sulphur bacteria from an environmental sample is

Providing mineral salts, organic carbon and light but excluding fixed nitrogen and filling the gaseous headspace with N2.