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APPLIED AND ENVIRONMENTAL MICROBIOLOGY, Sept. 1992, p. 3130-3135 0099-2240/92/093130-06$02.00/0
 

Summary: APPLIED AND ENVIRONMENTAL MICROBIOLOGY, Sept. 1992, p. 3130-3135
0099-2240/92/093130-06$02.00/0
Copyright C 1992, American Society for Microbiology
Dispersion of Small Ceramic Particles (A1203) with
Azotobacter vinelandii
TAO REN,1 NANCY B. PELLERIN,' GORDON L. GRAFF,2 ILHAN A. AKSAY,2'3
AND JAMES T. STALEY"*
Departments ofMicrobiology' and Materials Science and Engineering2 and Advanced Materials
Technology Center,3 University of Washington, Seattle, Washington 98195
Received 31 March 1992/Accepted 13 July 1992
The high surface charge of small ceramic particles such as alumina particles prevents them from dispersing
evenly in aqueous suspensions and forming high-density compacts. However, suspensions of 400-nm-diameter
alumina particles treated with alginate from the bacterium Azotobacter vinelandii were well dispersed. The
alginate bound firmlyto the particle surface and could not be removed by repeated washing with distilled water
(2.82 mg of the bacterial alginate adsorbed to 1 g of the alumina particles). Furthermore, A. vinelandii grew
and produced alginate in the presence of up to 15% (vol/vol) alumina particles. These results suggest that an
in situ process using this bacterium to coat ceramic particles with alginate might be developed. In in situ
processing experiments, the particle-packing densities were significantly increased and the viscosities of 5 and
10% (vol/vol) suspensions were reduced 4- and 60-fold, respectively, over those of controls. The bacteria were
readily removed from the alumina particles by washing.

  

Source: Aksay, Ilhan A. - Department of Chemical Engineering, Princeton University

 

Collections: Materials Science