Taxonomic characterization of novel aerobic bacteriochlorophyll-containing bacteria isolated from soil.

Abstract

Aerobic bacteriochlorophyll (BChl) a-containing bacteria (designated as strains NS89, NS102, and NS130) were isolated from soil samples in Japan and their taxonomic characteristics were investigated. These strains were obligately aerobic, Gram-negative, and non-motile cocci, and formed irregular colonies on agar media. The strains could not utilize methanol as a sole carbon and energy source and sulfate as a sole sulfur source. Strain NS130 required divalent cations (Ca 2+ or Mg 2+ ) for growth in liquid culture. The cations were not necessary for the growth of strains NS89 and NS102 in liquid culture, however, the cations promoted growth. Light stimulated the growth of strains NS89 and NS102, but not the growth of strain NS130. The absorption spectra of membrane fractions of strains NS89 and NS102 had a large peak at 856 nm that was derived from BChla, while the spectrum of strain NS130 had a large peak at 872 nm. Membrane fractions of the three strains showed photochemical activity. The guanine plus cytosine contents of DNA of strains NS89, NS102, and NS130 were 70.3, 71.0, and 70.5 mol%, respectively. The ubiquinone system of the strains was Q-10, and the major cellular fatty acid was octadecenoic acid (C 18:1 ) (57-68%). The three strains contained 2-hydroxy and 3-hydroxy fatty acids, and 2-hydroxyoctadecenoic acid (2-OH C 18:1 ) was 11-12%.