New Bacterial Group Named After ARS Scientist

Hespellia is the name of a new genus of bacteria discovered by Agricultural Research Service and cooperating scientists and posthumously named in honor of ARS microbiologist Robert B. Hespell. A genus is a specific taxonomic group of closely related species.

Scientists from the ARS National Center for Agricultural Utilization Research (NCAUR) in Peoria, Ill., and the University of Reading in the United Kingdom concluded the genus was new after comparing the bacteria's ribosomal gene, 16S rDNA, to other species and analyzing the new microbes' biochemical features. The team discovered the Hespellia bacteria while cataloging microbial species that inhabit swine manure and produce its offending odor.

Collecting such information can yield important clues for figuring out new ways of diminishing the odors, according to ARS microbiologist Terence R. Whitehead, a member of NCAUR's Fermentation Biotechnology Research Unit. New pig feed formulations with improved digestibility and novel waste-handling systems are two possibilities. Besides sulfides that contribute to swine manure's stink, the waste also emits gases like ammonia and methane that can be environmentally harmful, notes Whitehead.

He credits Hespell, who worked at NCAUR until his death in August 1998, with pioneering studies on the scientific description of anaerobic bacteria and their use in improving digestion in the rumen of cows and sheep. Anaerobes are organisms that thrive in oxygen-free environments--including those outside of animal hosts, such as manure storage pits and lagoons where manure is treated for use as fertilizer.

In the January issue of the International Journal of Systematic and Evolutionary Microbiology, Whitehead and co-authors Michael Cotta of NCAUR and Mathew Collins and Paul Lawson of the University of Reading describe two new species of Hespellia bacteria found growing in a pig manure pit near Peoria. Genetic analysis revealed that the Gram-positive, rod-shaped bacteria--H. stercorisuis and H. porcinia--are 97 percent identical to one another, but different enough from other anaerobes to warrant classification as members of a new genus.

ARS is the U.S. Department of Agriculture's chief scientific research agency.