Isolation and characterization of diazotrophs from the intestinal tract of an earthworm (Pheretima vittata)

Abstract

Microaerobic nitrogen-fixing bacteria were isolated from the intestinal tract of the earthworm (Pheretima vittata) collected from a cultivated field at Nara, Japan. Nitrogen-free semi-solid medium containing malic acid as a carbon source was used for the isolation. Physiological characteristics and partial nucleotide sequences of 16S rDNA of the isolates showed that all of the six isolates belonged to Klebsiella oxytoca. They exhibited an acetylene reduction activity of up to 50 nmol h−1 culture−1 in the semi-solid medium. © 2002 Taylor & Francis Group, LLC.