Vibrio diazotrophicus sp. nov., a Marine Nitrogen-Fixing Bacterium

Abstract

Facultatively anaerobic, nitrogen-fixing bacterial strains were isolated from sources as diverse as the gastrointestinal tracts of sea urchins collected in Nova Scotia, Canada, and the surfaces of reeds growing in a drainage ditch in Kent, England. These strains were placed in the genus Vibrio Pacini 1865 of the family Vibrionaceae on the basis of their morphological, physiological, and biochemical characteristics, as well as on the basis of the guanine-plus-cytosine contents of their deoxyribonucleic acids (45.9 to 47.2 mol%). They were clearly distinguished from strains of the currently recognized species in the genus Vibrio by a combination of diverse traits, including the production of nitrogenase, the inability to hydrolyze casein, deoxyribonucleic acid, gelatin, and Tween 80, the ability to ferment L-arabinose, cellobiose, salicin, and D-xylose, and the presence of an arginine dihydrolase system. Deoxyribonucleic acid homology studies supported recognition of these nitrogen-fixing strains as a new species, for which the name Vibrio diazotrophicus is proposed. Strain ATCC 33466 (= strain 1 = NS1) is the type strain.