Geoffrey Smith
Title: Professor
Research area: Environmental Microbiology
Office location: FH 363
Laboratory Location: FH 355/357
Email Address: gsmith@nmsu.edu
Office Phone: 575-646-
Lab Phone: 575-646-
Lab Webpage: ---
Research Interests:
Contamination of the United
States' groundwater with industrial wastes is a serious problem,
particularly considering that the nation's ground water provides
drinking water to an estimated 56% of U.S. households. New Mexico
obtains 90% of its drinking water from groundwater sources. I am
researching the bacteria, enzymes and genes involved in the microbial
biodegradation of environmental contaminants such as benzene, the
chlorofluoro carbons (CFCs) and the trihalomethane compounds such as
chloroform. The environments that I am interested in carrying out
these studies are in the groundwater of contaminated aquifers and in
wastewaters. Biodegradation activity (as monitored by gas
chromatography) is being studied under anaerobic conditions.
I am using DNA and RNA nucleic
acid probes of interest in natural samples such as
aquifers. I have developed a gene probe specific for the bacteria
which reduce nitrate to nitrogen gas (denitrifying bacteria); the gene
codes for the heme-type nitrite reductase enzyme. Other genes
specific for pollutant biodegradation pathways such as those of the
toluene-degradation (TOL) plasmid have been obtained for use in this
work. The gene probes are used to analyze the genetic potential
for biodegradation in samples such as the aquifer columns mentioned
above. Additionally, the probes can be used to indicate the
changes in microbial populations due to experimental perturbations such
as the imposition of anaerobic conditions. A major advantage of
DNA probe use is that the technique does not rely on the
microorganism's ability to grow in laboratory media, and thus the
technique has access to microbes previously undetected by other
methods. A related research interest is the improvement of
techniques to extract high-purity DNA from natural samples such as
aquifers and soils.
Selected Publications:
- Smith, G.B. and J.M. Tiedje (1992) Isolation and characterization
of a nitrite reductase gene and its use as a probe for denitrifying
bacteria. Applied and Environmental Microbiology 58:376-384.
- Smith, G.B. and A.G. Wollum (1993) Physicochemical and
D-galactose-mediated interactions in the attachment Bradyrhizobium
japonicum to roots of Glycine max. Canadian Journal of Microbiology
39:245-251.
- Sonier, D. N., N. L. Duran and G. B. Smith (1994) Dechlorination
of CFC-11 by sulfate-reducing bacteria from an aquifer contaminated
with halogenated aliphatic compounds. Applied and Environmental
Microbiology 60:4567-4572.
- Yu, Z. and G. B. Smith (1995) Chloroform dechlorination by a biological activated carbon microbial consortium from a denitrification tank. Applied and Environmental Microbiology