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Appl. Environ. Microbiol., 05 1995, 1750-1756, Vol 61, No. 5
MJ Gross and BE Logan
Seven chemicals, three buffers, and a salt solution known to affect
bacterial attachment were tested to quantify their abilities to enhance the
penetration of Alcaligenes paradoxus in porous media. Chemical treatments
included Tween 20 (a nonionic surfactant that affects hydrophobic
interactions), sodium dodecyl sulfate (an anionic surfactant), EDTA (a cell
membrane permeabilizer that removes outer membrane lipopolysaccharides),
sodium PPi (a surface charge modifier), sodium periodate (an oxidizer that
cleaves surface polysaccharides), lysozyme (an enzyme that cleaves cell
wall components), and proteinase K (a nonspecific protease that cleaves
peptide bonds). Buffers included MOPS [3-(N-morpholino)propanesulfonic
acid], Tris, phosphate, and an unbuffered solution containing only NaCl.
Transport characteristics in the porous media were compared by using a
sticking coefficient, alpha, defined as the rate at which particles stick
to a grain of medium divided by the rate at which they strike the grain.
Tween 20 reduced alpha by 2.5 orders of magnitude, to alpha = 0.0016, and
was the most effective chemical treatment for decreasing bacterial
attachment to glass beads in buffered solutions. Similar reductions in
alpha were achieved in unbuffered solutions by reducing the solution ionic
strength to 0.01 mM. EDTA, protease, and other treatments designed to alter
cell structures did not reduce alpha by more than an order of magnitude.
The number of bacteria retained by the porous media was decreased by
treatments that made A. paradoxus more hydrophobic and less
electrostatically charged, although alpha was poorly correlated with
electrophoretic mobility and hydrophobicity index measurements at lower
alpha values.(ABSTRACT TRUNCATED AT 250 WORDS)
Copyright © 1995, American Society for Microbiology
Influence of different chemical treatments on transport of Alcaligenes paradoxus in porous media
Department of Chemical and Environmental Engineering, University of Arizona, Tucson, USA.
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