Soil Bacteria

John W. Patching John.Patching at UCG.IE
Thu Oct 13 07:15:46 EST 1994


A recent message from Kevin O Connel talks about the "accidental" isolation
of a thermophillic bacillus from soil by a student and says
"having the students look at warmer temps as well would also be productive,
and lead to some nice discussion on  bacterial diversity and microbial
ecology."
Indeed it would -  but can I warn correspondents about letting spores from
thermophillic bacteria loose in the lab. Once they get out they are VERY
difficult to get rid of!  We have grown thermophillic bacilli in
fermenters.  In spite of full autoclaving of equipment etc., thermophillic
contaminants can still pop up when other high temperature fermentations are
carried out. 
If , in spite of this,  you still fancy isolating thermophils, why not go
for something really unusual, and look for organisms which grow both at
temperatures above 50 degrees C and pH values above 9.5!  Drs Wiegel and
Engel (Dept Microbiology, University of Georgia) have isolated several
strains of this type. Unfortunately, I cannot give a reference for this
work, which I heard presented at this years Boston meeting of the Society
for Industrial Microbiology (abstract S107 if you have the programme!). The
interesting point is that  most of these strains were easily isolated from
sewage plants, manure and sediments.  Another aspect  of some of  them
which might prove interesting to students is  their extremely fast growth
rates.  "Thermorhizocus celer" has a doubling time of 13minutes at pH8.5
and 65 degrees C!

John W. Patching
The Martin Ryan Marine Science Institute
University College Galway, Ireland

Email: John.Patching at UCG.IE
Phone: +353-91-24411 Ext 2398
Fax:       +353-91-750456





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