Erythrobacter longus gen. nov., sp. nov., an Aerobic Bacterium Which Contains Bacteriochlorophyll a

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Abstract
Four orange-pigmented and seven pink-pigmented strains of bacteria which contained bacteriochlorophyll a were isolated from high-tidal seaweeds, such as Enteromorpha linza (L.) J. Ag. and Porphyra sp. All of the isolates were gram negative. The orange-pigmented bacteria were rods with parallel sides and rounded ends, and the pink-pigmented bacteria were ovoids and short rods. All were motile by means of subpolar flagella. None of the strains produced growth anaerobically in the light. No growth occurred with an atmosphere containing H2 and CO2. All of these bacteria grew aerobically and utilized glucose, pyruvate, acetate, butyrate, and glutamate as sole organic carbon sources. The best growth occurred on complex media formulated for heterotrophic marine bacteria. Biotin was required. Oxidase and catalase were present. Small amounts of acid were produced from a wide range of carbohydrates under microaerobic conditions. Gelatin was hydrolyzed. The strains which we investigated fell into the following three clusters: cluster A, all of the orange strains; cluster B, three pink strains; and cluster C, four pink strains. The strains of clusters B and C required thiamine and nicotinic acid and were susceptible to streptomycin. Tween 80 was hydrolyzed and phosphatase activity was produced by the strains of clusters A and B. Pantothenate was required only by the strains of cluster C. The guanine-plus-cytosine contents of the deoxyribonucleic acids of these organisms ranged from 60 to 64 mol%. These organisms are recognized here as members of a new genus, Erythrobacter. Although these organisms did not grow phototrophically, the presence of bacteriochlorophyll a indicated that they are most closely related to the Rhodospirillaceae. The type species is Erythrobacter longus, the type strain of which is an orange strain, OCh101 (= IFO 14126).