Selective enrichment and isolation of Rhodopseudomonas palustris using trans-cinnamic acid as sole carbon source

Enrichment cultures for anoxygenic phototrophs capable of using cinnamic acid as sole organic carbon source consistently yielded the nonsulfur purple bacterium Rhodopseudomonas palustris. Pure cultures of R. palustris obtained from the enrichments grew photoheterotrophically on cinnamate and benzoate as well as on derivatives of these compounds. Photosynthetic growth on cinnamate was greatly stimulated by addition of exogenous CO2, and resulted in breakage of the aromatic nucleus. Growth yield studies suggested that cinnamate was converted by R. palustris to intermediates that can be quantitatively assimilated into cell material.