Myxococcus xanthus biomass as biosorbent for lead

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