COPPER ADSORPTION BY INACTIVATED CELLS OF MUCOR-ROUXII - EFFECT OF ESTERIFICATION OF CARBOXYL GROUPS

Inactivated copper-sensitive and copper-tolerant strains of Mucor roux ii cultured at high copper concentration were tested for their potenti al to adsorb Cu(II) ions from solution. We performed batch experiments to determine the pH profile for Cu(II) binding, binding capacity, and the possibility of removing the Cu(II) that had been adsorbed. The bi omasses studied showed a high affinity for Cu(II) ions as the pH incre ased from 2 to 5. The copper-tolerant strain exhibited a higher copper adsorption than the copper-sensitive strain. Most of the Cu(II) adsor bed by the inactivated cells was desorbed by treatment with 0.1 M HCl. We investigated one of the mechanisms involved in Cu(II) binding thro ugh chemically modifying the possible carboxyl groups present on the i nactivated cells of Mucor rouxii by esterification with methanol. Cu(I I) binding decreased approximately 25% after the carboxyl groups were esterified. The Cu(II) binding ability of the esterified carboxyl grou ps was regained after base hydrolysis. These preliminary findings sugg est that the carboxyl groups could be one of the mechanisms responsibl e for Cu(II) binding. This phenomenon can have useful applications for metal removal from contaminated water.