AUTHOR=Heylen Kim , Keltjens Jan 

TITLE=Redundancy and modularity in membrane-associated dissimilatory nitrate reduction in Bacillus

JOURNAL=Frontiers in Microbiology

VOLUME=3

YEAR=2012

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2012.00371

DOI=10.3389/fmicb.2012.00371

ISSN=1664-302X

ABSTRACT=<p>The genomes of two phenotypically denitrifying type strains of the genus <italic>Bacillus</italic> were sequenced and the pathways for dissimilatory nitrate reduction were reconstructed. Results suggest that denitrification proceeds in the periplasmic space and in an analogous fashion as in Gram-negative organisms, yet with the participation of proteins that tend to be membrane-bound or membrane-associated. A considerable degree of functional redundancy was observed with marked differences between <italic>B. azotoformans</italic> LMG 9581<sup>T</sup> and <italic>B. bataviensis</italic> LMG 21833<sup>T</sup>. In addition to the already characterized menaquinol/cyt <italic>c</italic>-dependent nitric oxide reductase (Suharti et al., <xref ref-type="bibr" rid="B105">2001</xref>, <xref ref-type="bibr" rid="B104">2004</xref>) of which the encoding genes could be identified now, evidence for another novel nitric oxide reductase (NOR) was found. Also, our analyses confirm earlier findings on branched electron transfer with both menaquinol and cytochrome <italic>c</italic> as reductants. Quite unexpectedly, both bacilli have the disposal of two parallel pathways for nitrite reduction enabling a life style as a denitrifier and as an ammonifying bacterium.</p>