soil bacteria

Mike Powell mpowell at
Tue Oct 11 08:42:33 EST 1994


> As a portion of a micro lab, I have had my students isolate bacteria from
> soil. We are now in the process of identifying the isolates. Pseudomonas
> and Bacillus spp. are predominant, but we have isolated a small Gram - cocci
> (tiny). Can anyone provide a list of typically isolated bacteria from soil?
> Any suggestions as to the identity of the Gram negative cocci?
> Our isolation method has selected for aerobes and facultative anaerobes that
> are non-fastidious (grow well on trypic soy agar at 37 C).Thanks in advance.


  I can remember doing something similar in a class project for 
micro lab.  Interestingly we tried using different using different
media and conditions.  At the time the results suprised me but
many soil organisms don't particularly care for the rich media used
to grow clinical isolates (ie Tsoy based etc.). I can't help with
the identification but I just wanted to mention that we found that
the lower the nutrient content the more diversity of organisms we
were able to isolate.  A good medium was plain "water agar".  Of 
course one is only able to grow a tiny fraction of what is present
typically... but try less complex media and a lower than "body"
temperature sometime.. you might be suprised too.


When the going gets tough, I fall behind.
Mike Powell, PhD
Laboratory of Molecular Genetics
National Institutes of Health
Bldg 6B  Rm 216
Ph: 301 496 5538  Fax: 301 496 0243
email: mpowell at

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