Using Sucrose Gradients to Separate
Biologically Produced Tellurium Metas and Bacterial Cells with Detection
by HGAAS and/or ICP/AES
J. Swearingen, Jr.
and T. G. Chasteen
Department of Chemistry
Sam Houston State University
Huntsville, Texas 77341-2117
A separation method involving sucrose gradients was developed
in order to determine elemental tellurium produced by bacterial cells of
Pseudomonas fluorescens K27 amended with soluble but toxic tellurium salts.
Hydride generation atomic absorption or inductively coupled plasma spectrometry
was used in order to determine the concentration of tellurium in each individual
layer of the (tube-based) gradient following centrifugation with solids
harvested from an anaerobic bioreactor vessel grown far into stationary
phase (72h). Samples were also analyzed by UV/Vis spectrophotometry in
order to determine the bacterial cell density of each sucrose layer. Using
sucrose concentrations at 0.1M, 1.5M, 2M, and 2.5M, the K27 bacterial cells
concentrated at the top of the 2.5M sucrose layer.