Comparative studies on metal biosorption by two strains of Cladosporium cladosporioides

Two strains of a fungus, Cladosporium cladosporioides I and C cladosporioid es 2 showed different metal biosorption properties. Strain I showed prefere ntial sorption of gold and silver, while strain 2 could bind metals such as copper and cadmium in addition to gold and silver. Strain I had a cell-wal l hexosamine content of 0.1%. X-ray photoelectron spectroscopy (XPS) and Fo urier transform infra-red spectroscopy (FTIR) analyses indicated that nitro gen was not involved in metal biosorption by the strain. In strain 2 the ce ll-wall hexosamine content was 150 times that of strain 1. These results in dicated that hexosamine was responsible for non-specific metal binding whil e cell-wall polymers other than hexosamines had a role in conferring select ivity in precious-metal binding. (C) 2001 Elsevier Science Ltd. All rights reserved.