CHEMICAL AND ENZYMATIC EXTRACTION OF HEAVY-METAL BINDING POLYMERS FROM ISOLATED CELL-WALLS OF SACCHAROMYCES-CEREVISIAE

Isolated cell walls of the yeast Saccharomyces cerevisiae were treated by either chemical (alkali and acid) or enzymatic (protease, mannanas e or beta-glucuronidase) processes to yield partially purified product s. These products were partially characterized by infrared analysis. T hey were subsequently reacted with heavy metal cation solutions and th e quantity of metal accumulated by the cell wall material determined. The Cu2+ ion (0.24, 0.36, 1.12, and 0.60 mu mol/mg) was accumulated to a greater extent than either Co2+ (0.13, 0.32, 0.43, and 0.32 mu mol/ mg) or Cd2+ (0.17, 0.34, 0.39, and 0.46 mu mol/mg) by yeast cell wall s, glucan, mannan, and chitin, respectively. The isolated components e ach accumulated greater quantities of the cations than the intact cell wall. Removal of the protein component of the yeast cell wall by Pron ase caused a 29.5% decrease in metal accumulation by yeast cell walls per mass, indicating that protein is a heavy metal accumulating compon ent. The data indicate that the outer mannan-protein layer of the yeas t cell wall is more important than the inner glucan-chitin layer in he avy metal cation accumulation. (C) 1994 John Wiley & Sons, Inc.