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<A NAME=chipcritter>
<FONT SIZE="6" COLOR="#001C87">Chip Critters</FONT>


<FONT COLOR="#006633" SIZE="+1">Engineers meld bacteria and silicon chips

to help clean up polluted sites</FONT>

Stuff that is noxious waste to us may be a tasty meal for other organisms. That is the theory
behind <a href="#cc1">bioremediation</a>, a technique which
uses plants and bacteria to clean up polluted soil and water. Certain organisms can eat and
digest industrial toxins, breaking them down into far less harmful by-products. That skill, it
turns out, can also be used to help locate and map out the areas in need of
ecological rehabilitation.

<a href="#cc2">Gary Sayler</A>, a microbiologist at the University of Tennessee
in Knoxville, was trying to remediate water using a modified version of the bacterium
Pseudomonas fluorescens HK44. Sayler had inserted genes into the bacterium that cause it to
emit a blue-green light as it digests hazardous wastes. The faint glow of the Pseudomonas
fluorescens shows which areas are tainted, how concentrated the pollutant is, and whether
there are enough of the bacteria in the right places to clean up the mess. In order to monitor
the light output, however, Sayler had to use bulky equipment and fiber optic cable,
limiting the size of the area that he could study. There were also practical concerns: what was
to stop the bacteria from washing away or growing out of control?</font>