Fixation of spent Saccharomyces cerevisiae biomass for lead sorption

Spent Saccharomyces cer cerevisiae cells from a beer fermentation process w ere evaluated for lead cation sorption. The crude biomass was washed with w ater and acetone prior to any other treatment. Although the washed biomass showed substantial lead ion sorption it was susceptible to microbial spoila ge. Different aldehydes were tested as chemical fixation agents; however, m ost of them caused drastic lowering of the metal uptake capacity. However, benzaldehyde was not only an excellent fixation agent, but the biomass trea ted with it also retained its original lead sorption capacity. A mechanism for the fixation process is suggested.