Growth rates of anaerobes

Andreas Brune Andreas.Brune at uni-konstanz.de
Wed Mar 1 03:00:48 EST 1995


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



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