LONG-TERM INTRACELLULAR CHROMIUM PARTITIONING WITH SUBSURFACE BACTERIA

Subsurface bacteria were used to study the kinetics of chromate uptake and the internal distribution of the chromium that is taken up by the se cells using two equilibration periods (1 and 50 days). Cells that w ere exposed to chromate for 50 days (to simulate in-situ conditions) w ere able to sequester up to 200% more chromium per unit mass of cells than were cells that were exposed for only 1 day. Chromium distributio ns showed an increase in chromium sorption by the cell wall, by the me mbrane and ribosome, and by the soluble fraction after a 50-day equili bration period compared to after 1 day of equilibration. Killed cell c ontrols suggest that active transport of chromate is the method of int racellular accumulation during the 50-day equilibration period.