The sorption of metals to Bacillus subtilis walls from dilute solutions and simulated Hamilton Harbour (Lake Ontario) water

Abstract

Purified cell walls of Bacillus subtilis were reacted with various metals in dilute solutions and a simulated Hamilton Harbour (Lake Ontario) water. Atomic absorption spectrophotometry revealed that iron was sorbed to the walls preferentially and caused the walls to adhere together to form macroscopic floes, which were easily sedimented by gravity. Electron microscopy and energy dispersive X-ray analysis of the floes showed that the bacterial walls were embedded in an iron matrix presumed to be iron oxyhydroxide. The sorption of iron to the walls was also found to enhance the uptake of other metals such as chromium and aluminum. This sorption suggests that bacteria may play a role in the initial formation of metal rich sediments. It may also have important implications for the general transport of metals to the sediments from the water column in fresh water environments like Hamilton Harbour by all types of particulate biological debris.Key words: metal sorption to bacterial walls.