Mutant of Clostridium pasteurianum That Does Not Fix Nitrogen

Abstract

A stable, non-nitrogen-fixing mutant of Clostridium pasteurianum W5 was isolated. The mutant has the same growth rate as the wild type on ammonia nitrogen, but is not able to grow on N 2 . Cell-free extracts of the derepressed mutant are unable to fix nitrogen, or reduce the alternate substrates of nitrogenase such as cyanide, azide, or acetylene. Recombination with wild-type components from a diethylaminoethyl cellulose column indicates that the mutant contains component II, but is lacking component I activity.