Isolation and screening of glucose oxidase producing microorganisms from natural sources.

Among 1486 mould strains isolated from natural sources (screened for extracellular glucose oxidase) only 119 (Aspergillus and Penicillium) showed this enzyme activity. As the best glucose oxidase producer, A. niger 0-1 was isolated from decaying tree.

Glucose oxidase biosynthesis using immobilized mycelium of Aspergillus niger.

A simple method is described for the immobilization of Aspergillus niger GIV-10 which produces an extracellular glucose oxidase. A. niger conidia were immobilized on sintered glass Raschig rings, pumice stones or polyurethane foam.

Screening of microorganisms for improvement of beta-galactosidase production.

The strain of Penicillium notatum 1 most effective for producing beta-galactosidase (see lactase 3.2.1.

Selection of amylolytically active Aspergillus niger mutants to 2-deoxy-D-glucose.

As a result of mutagenization and passaging on 2-deoxy-D-glucose containing medium, 10 Aspergillus niger strains resistant to this agent were obtained. These showed (with one exception) an increase in the activity of glucoamylse, the level of which ranged widely in individual cases from several to over 200% in comparison with the parent strain. A weaker rate of glucose accumulation in derepressed strains may account for the fact that the mechanism of their resistance to deoxyglucose is connected with disturbance of the system of glucose transport.

Pectinolytic activity of revertants of auxotrophic strains of Aspergillus niger.

From conidia of 4 different auxotrophic A. niger strains 400 spontaneous revertants (100 from each strain) were obtained, and in one case additionally 100 revertants induced by mutagens (UV+NTG). The revertants showed a considerable differentiation with regard to the total pectinolytic activity.