Cryptococcus neoformans strains were isolated from clinical source taken from the University of Benin Teaching Hospital (UBTH) and environmental source taken from New Benin Market. Two strains were selected; clinical isolate 4832 and environmental isolate NBM5. They were determined to be of two different mating types, due to differences in their susceptibility to the antifungal agent fluconazole. In order to check the involvement of mating type locus in the virulence of C. neoformans, congenic mutants were developed.
Aspergillus niger popularly known as industrial workhorse due to its fitness for industrial fermentation, has the potentials to secret citric acid. In view of surges in demand and growing markets for citric acid, the major attempt in this work was to determine how the product titres can be maximized. A. niger strains were isolated from various food substances. These strains were exposed to UV radiation at 356nm followed by subsequent subjection of the mutant strains to a medium containing chlorate as mutagen.