Two cadmium resistant mutants (Cd1 and Cd2) of Aspergillus niger, among the six isolated by mutagenization
with N-methyl N¢-nitro-N-nitrosoguanidine (MNNG) at pH 6×4 were selected for the study. Analysis of lipid
composition of the mutants and the wildtype indicated that total lipid as well as individual lipids of the cadmium
resistant mutants were changed as compared with that of the wildtype. The increased activities of metallothionein
and reduced activities of D-xylose isomerase and L-phenylalanine ammonia lyase in cell free extract
of the cadmium resistant mutants suggested that mutants could allow high concentration of cadmium salt as
compared with that of the wildtype. The respiratory activity and intracellular as well as extracellular Cd2+ concentration
of the mutants reflected the high tolerance of the Cd mutants to cadmium ion.