axu at ornl.gov (A. H. Curtis) wrote:
>In article <3ih2pd$dpj at mserv1.dl.ac.uk> <Enevold.Falsen at alinks.se> writes:
>>Most of our denitrifiers are strict aerobic organisms like
>>Pseudomonas aeruginosa, Alcaligenes, etc.
>>Denitrifiers are strict anaerobes or microaerophilic.
>
Let's get a few things right:
1. Denitrifying organisms, which perform a nitrate respiration and
reduce nitrate to N2 are *usually* aerobic bacteria which (in the
absence of O2) use nitrate as an alternate electron acceptor. As
Ernevold said, typical representatives are among the pseudomonads.
2. I am not aware of a microaerobic denitrifyer, which -- when growing
aerobically -- is sensitive to ambient oxygen concentrations. There
is, however, *ONE* exception to the rule that denitrifyers are
aerobic organisms, in form of an *ANAEROBIC* organism (unable to
use oxygen as terminal electron acceptor) performing a nitrate
respiration.
3. Ernevold said that "most of the facultative anaerobic organisms
we have hate to be grown under strict anaerobic conditions."
WHY would a facultatively anaerobic organism (i.e., an organism
which by definition growths both with or without using O2
as electron acceptor) HATE to grow anaerobically? Are you routinely
growing anaerobes on media containing reducing agents? Not all
anaerobes like that.
Regards,
Andreas
Dr. Andreas Brune Phone: +49-7531-883282
Mikrobielle Oekologie Fax: +49-7531-882966
Universitaet Konstanz E-mail: Andreas.Brune at uni-konstanz.de
