The external pH appeared to be the main factor governing oxalic acid production by Aspergillus niger. A glucose-oxidase-negative mutant produced substantial amounts of oxalic acid as long as the pH of the culture was 3 or higher. When pH was decreased below 2, no oxalic acid was formed. The activity of oxaloacetate acetylhydrolase (OAH), the enzyme believed to be responsible for oxalate formati...

Different agricultural residues were considered in this study for their ability to support cellulolytic enzyme production by Aspergillus niger. A total of eleven agricultural residues including finger millet hulls, sorghum hulls, soybean hulls, groundnut husk, banana peels, corn stalk, cassava peels, sugarcane bagasse, saw dust, rice straw and sheanut cake were subjected to three pretreatment (...

Monosulphides of O-phenyl-N-substituted phenylcarbamates were prepared by the reaction between Ophenyl-N-substituted phenylcarbamates and sulphur dichloride while the corresponding disulphides were prepared by the reaction between O-phenyl-Nsubstituted phenylcarbamates and sulphur monochloride. The synthesized compounds were characterized by elemental analysis, thin layer chromatography (TLC), ...

The leaf and stem of cordia macleodii plant were investigated for evaluating antibacterial and antifungal properties. Different extracts of leaf and stem viz. double distilled water, methanol, ethyl acetate ane n-hexane were collected and content was optimized for the maximum amount of extraction with varying time of 6 and 12 h. The extracts were tested for their antimicrobial activities agains...

Three different Aspergillus Niger MTCC strains (872, 1785 and 2208) were used for the production of chitosan. Multivariate growth mediums in varying incubation periods were analyzed for the production. The produced chitosan was characterized by its physical appearance, moisture content (by means of gravimetric method), percentage of ash and solubility (through the Association of Official Agricu...

We sought to determine if sufficient redundancy exists between specific IgE testing for Aspergillus fumigatus and Aspergillus niger to eliminate one of the assays in determining Aspergillus hypersensitivity. We reviewed regional laboratory results comparing A fumigatus-specific IgE with A niger-specific IgE using the Pharmacia UniCAP system (Pharmacia, Kalamazoo, MI). By using the Fisher exact ...

Aspergillus niger has an innate ability to secrete various organic acids, including citrate. The conditions required for A. niger citrate overproduction are well described, but the physiological reasons underlying extracellular citrate accumulation are not yet fully understood. One of the less understood culture conditions is the requirement of growth-limiting iron concentrations. While this ha...

OBJECTIVE The evaluation of the Sensititre YeastOne and Etest methods for determining susceptibility to amphotericin B and itraconazole by comparing the MICs obtained by these methods at different times of reading with those of the M38-A broth microdilution method. METHODS Sixty-three clinical isolates of Aspergillus spp. (23 Aspergillus flavus, 24 Aspergillus fumigatus, nine Aspergillus nige...

AIMS To examine whether water activity (aw) in combination with low concentration of fungicides can be used to effectively control Aspergillus niger van Tieghem growth in cultural medium, the Sabouraud dextrose agar (SDA). The data would be used as baseline information for reducing A. niger contamination in insect artificial diets. METHODS AND RESULTS Aspergillus niger was isolated from an in...