Aspergillus section Nigri includes some of the most important species for biotechnology and its species are of widespread occurrence. During our surveys of various food products and tropical soil we isolated several aspergilli belonging to section Nigri. In this paper, four new sclerotium and/or ochratoxin A producing species belonging to this section are proposed. In addition, based on a polyp...

The possible use of cotton waste as a carbohydrate source of citric acid production by Aspergillus niger was examined. No citric acid was produced when A. niger was grown on cotton waste as a sole carbon source. In two-stage fermentations, however, mycelium obtained from surface cultures in cotton waste medium yielded more citric acid when transferred to sucrose-containing media than when direc...

Maintaining optimum quality and eliminating dates of contamination, cleanup and packaging to extend the shelf life is one of the country's priorities and policies. Edible coatings with vegetable oils are one way to prevent the growth of microorganisms. In this study, the influence of the coating with natural zein and chitosan polymers along with the essential oil of Roman anise on the microbial...

chromium is one of the major causes of environmental pollution. to remove heavy metal ions from water, microorganisms can be used. in this study, dead fungal biomass of aspergillus niger is used. the biomass was boiled in 0.5 n naoh solutions to increase the metal removal capacity of a.niger and was applied when the ph of wash solution was in the normal range. the optimum adsorption ph value ob...

Bioconversion of waste newspaper into fermentable sugars at different temperatures with Aspergillus niger cellulase concentrationsJ Boitumelo M Sibiya, J Pieter H van Wyk

Endo beta-1,4-mannanases (beta-mannanases, EC 3.2.1.78), belonging to CAZy GH5 and GH26 families, catalyze the hydrolysis of structurally different mannans. In this study, the mannanase encoding gene of Aspergillus aculeatus VN was expressed in Aspergillus niger D15#26 using pAN 52-4 vector, under the control of PgpdA promoter and TtrpC terminator. In order to improve the hydrolytic capacity of...

The purpose of the present investigation was to enhance the production of industrially important enzyme lipase by subjecting the wild lipase producing fungal strains i.e. Aspergillus niger, Rhizopus microsporus and Penicillium atrovenetum to various doses of gamma irradiation (20, 40, 60, 80, 100, 120, 140 and 160 Gy). The isolation and lipolytic activity of selected mutant derived strains is d...

Ochratoxin A (OTA), a potentially carcinogenic mycotoxin which contaminates grains, is produced by several Aspergillus species. A comparative sequence analysis of the OTA-producing Aspergillus ochraceus fc-1 strain and other Aspergillus species was performed. Two new OTA-related polyketide synthase (PKS) (AoOTApks) genes were identified. The predicted amino acid sequence of AoOTApks-1 displayed...

The objective of this study was to isolate and identify fungal species found in natural association with adults of Musca domestica. The adult insects were collected from two natural breeding grounds: hog pens and an urban sanitary landfill. The isolated fungi were identified as: Aspergillus flavus (23.8%), A. niger var. niger (14.4%), Penicillium corylophilum (21.4%), P. fellutanum (11.9%), Cla...

Aureobasidium pullulans strain Y117 was transformed to hygromycin resistance using plasmid pDH33, which contains the bacterial hygromycin B phosphotransferase gene (hph) fused to promoter elements of the Aspergillus niger glucoamylase gene (glaA). Southern hybridizations of transformants revealed multiple, integrated copies of the vector. The glaA promoter was not induced by starch in A. pullul...