ISSN: 0022-1198
CODEN: JFSCA
Published Online: 1 September 2004
Page Count: 7

Stable Isotope Ratios as a Tool in Microbial Forensics—Part 1. Microbial Isotopic Composition as a Function of Growth Medium?
Kreuzer-Martin, HW
Stable Isotope Ratio Facility for Environmental Research, Utah

Ehleringer, JR

Dorigan, JV
Central Intelligene Agency, DC

Chesson, LA
Stable Isotope Ratio Facility for Environmental Research, Utah

Lott, MJ

(Received 29 June 2003; accepted 28 March 2004)

Abstract

The stable isotope ratios of a seized pathogen culture could potentially reveal information about the environment in which the agent was produced. In this paper we describe general relationships between stable isotopes of carbon, nitrogen, and hydrogen in bacteriological culture media and spores of Bacillus subtilis, an endospore-forming soil bacterium. In numerous media that varied both in nutrient composition and water stable isotope ratios, medium to spore enrichment in carbon isotopes was 0.3 ± 2.0% (parts per thousand), and in nitrogen, 4.5 ± 0.7%. We achieved mass balance for the contribution of hydrogen isotopes from nutrients (70%) and water (30%) to spores in independent experiments by varying the isotope ratios of nutrients or water. A model was derived for predicting the isotope ratio values of spores from those in nutrients and water.

Keywords:
forensic science, stable isotopes, isotope ratio mass spectrometry (IRMS), Bacillus subtilis, spores, bacteria, biological agents, bioweapons, bioterrorism

Paper ID: JFS2003226
DOI: 10.1520/JFS2003226
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