soil bacteria

John Bowman jbowman at
Tue Oct 11 12:51:28 EST 1994

In article <mpowell-111094084233 at> mpowell at (Mike Powell) writes:
>From: mpowell at (Mike Powell)
>Subject: Re: soil bacteria
>Date: Tue, 11 Oct 1994 13:42:33 GMT


>> 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.

Dear  Mike

 Gram-negative cocci from soil are sought of unusual as most Gram neg. bugs  
tend to be rods. Check the gram-stain to see if they are consistently 
coccus-shaped. If they are truly cocci the strain could belong to the genus 
Paracoccus which is fairly common in soil. Paracoccus strains are non-motile, 
strictly aerobic, oxidase positive and colonies have a white to an off 
white pigmentation. Paracoccus strains can denitrify (nitrate is reduced to 
nitrogen gas) a very distinctive trait of the genus. Other possibilities exist 
but you may have to consult Bergey's Manual for additional information.  Any 
other questions please send e-mail  jbowman at,

Good Luck !

John Bowman Ph D.
Univ. Tennessee


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