6533b874fe1ef96bd12d60d4

RESEARCH PRODUCT

Anaerobic respiration of Bacillus macerans with fumarate, TMAO, nitrate and nitrite and regulation of the pathways by oxygen and nitrate

subject

description

In Bacillus macerans, anaerobic respiratory pathways and the regulation of facultatively anaerobic catabolism by electron acceptors were analysed. In addition to fermentative growth, B. macerans was able to grow anaerobically by fumarate, trimethylamine N-oxide, nitrate, and nitrite respiration with glycerol as donor. During growth by fumarate respiration, a membrane-bound fumarate reductase was present that was different from succinate dehydrogenase. The end product of nitrate and nitrite respiration was ammonia. No N2 or NO and only traces of N2O could be detected. O2 repressed the activity of nitrate and fumarate reductases and the fermentation of glucose, presumably at the transcriptional level. Nitrate repressed fumarate reductase activity and partially glucose fermentation. Thus energy metabolism and the regulatory hierarchy with respect to the use of electron acceptors were very similar to that known from E. coli; B. macerans can be regarded as a truly facultative anaerobic bacterium. In addition, the anaerobic growth capabilities of some other Bacillus strains are described.