Impact of
Extracellular Polymers Produced by Soil Microorganisms on Lindane
Transport
Abstract
Transport of a model pesticide (lindane) was enhanced by the
extracellular polymers (ECPs) produced by soil microorganisms. ECPs,
produced by Gram-negative and Gram-positive microorganisms, main
components of which are polysaccharides, proteins, and nucleic acids can
act to enhance this transport through porous media. Column studies for
Escherichia coli JM109, Bacillus subtilis, Pseudomonas aeruginosa over a
range of physiological states were conducted and the results showed that
the enhancements of the ECPs on lindane transport were strain specific and
were related to microorganisms' physiological states. The ECPs produced by
Gram-negative microorganisms worked more efficiently than those of
Gram-positive microorganisms. In addition, ECPs seemed to have a greater
enhancement effect when produced by bacterial microorganisms in the
stationary state (deposition coefficient value of 2.06 hr-1 for E. coli
JM109 on silica gel) as determined by Adenosine Triphosphate (ATP)
analysis than when produced in logarithmic (2.34 hr-1) and decay states
(2.25 hr-1). Infrared Spectroscopy (IR) study of the ECPs found that the
compositions, which were composed of both hydrophilic and hydrophobic
functional groups, were different for ECPs that had different enhancement
effect on lindane transport. It was also concluded that the hydrophicility
of the ECPs was the limiting factor for the enhancement effect.
Key words: lindane, transport, Escherichia coli,
Bacillus subtilis, Pseudomonas aeruginosa, extracellular polymers (ECPs),
physiological states.
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