This paper deals with lead biosorption by Myxococcus xanthus biomass i
n which dry biomass, accumulating up to 1.28 mmol of lead g(-1), is de
monstrated to be a more efficient biosorbent than wet biomass. Dry bio
mass biosorption was found to be very rapid, reaching equilibrium afte
r 5-10 min. Culture age, the initial lead concentration and pH affecte
d this process, but temperature did not. Furthermore, by using sodium
citrate as a desorbent agent, 92.17% of the biosorbed lead could be re
covered. It was also established that the biosorbed lead is located on
the cellular wall and within the characteristic extracellular polysac
charide of this micro-organism.