Induction of glucose oxidase, catalase, and lactonase in Aspergillus niger

Abstract

The induction of glucose oxidase, catalase, and lactonase activities was studied both in wild-type and in glucose oxidase regulatory and structural mutants of Aspergillus niger. The structural gene for glucose oxidase was isolated and used for Northern analysis and in transformation experiments using various gox mutations. Wild-type phenotype could be restored in the glucose oxidase-negative mutant (goxC) by transformation with the structural gene. We conclude, therefore, that the goxC marker which is located on chromosome 2 represents the structural gene of glucose oxidase. Glucose and a high oxygen level are necessary for the induction of all three enzyme activities in the wild-type strain and it was shown that both glucose and oxygen effects reflect regulation at the transcriptional level. The goxB mutation results in constitutive expression of all three activities although modulated to some extent by the carbon source. The goxE mutation only has an effect on lactonase and glucose oxidase expression and does not relieve the necessity for a high oxygen level. Catalase and lactonase could not be induced in the glucose oxidase-negative strain (goxC). Addition of H2O2 resulted in the induction of all three enzymes in the wild-type without glucose being present. The H2O2 induction is probably mediated by the goxB product. Besides the H2O2 induction there is still an effect of the carbon source on the induction. A model for induction of glucose oxidase, catalase, and lactonase in A. niger is discussed.(ABSTRACT TRUNCATED AT 250 WORDS)

Organic Acid Production by Filamentous Fungi

“…The FAD is reduced in the course of oxidizing glucose to gluconic acid, and the subsequent oxidation of the reduced FAD by molecular oxygen generates hydrogen peroxide (Gibson et al, 1964). Both glucose oxidase and gluconolactonase are located outside the plasma membrane and by activity staining and immunocytochemical staining glucose oxidase appears to be associated specifically with the cell wall in A. niger N400 (Witteveen et al, 1992). This is consistent with the observation that glucose oxidase from A. niger is glycosylated (Swoboda and Massey, 1965;O'Malley and Weaver, 1972), a general characteristic of fungal extracellular enzymes.…”

“…This emphasizes the need for catalase or some other mechanism of removing the hydrogen peroxide. In A. niger, there are two constitutive catalases and two catalases induced by dissolved oxygen concentrations of 30% or greater (Witteveen et al, 1992). Both the induced and constitutive pairs of catalases consist of one intracellular and one extracellular enzyme.…”

“…The importance of catalase is reflected in the design of a patented process for gluconic acid production by enzymes derived from A. niger where the catalase to glucose oxidase ratio is 200 or greater based on activity (Vroemen and Beverini, 1999). The identification of a large number of mutants affecting glucose oxidase production indicates that the expression of this enzyme, and gluconic acid production as a whole, is subject to complex regulation as are other organic acid production processes Witteveen et al, 1990Witteveen et al, , 1993. Although gluconic acid production by fermentation of glucose with A. niger is in current practice, in the future it is likely that an enzymatic process will be utilized if glucose oxidase can be produced economically and in a form stable to the process conditions.…”

Purification and Characterization of an Intracellular Catalase‐Peroxidase from Penicillium Simplicissimum

“…Three different catalases were detected in Neurospom cra,ssu (Chary and Natvig, 1989) and four in Aspergillus niger (Witteveen et al, 1992). In A. niger two catalases are located peripheral to the outer cell membrane.…”

“…Eucaryotic catalases are commonly located in peroxisomes but have also bcen found in the periplasm of the ligninolytic fungus Phanerochaete chrysosporiurn (Forney et al, 1982) and the ccll wall of the plectomycete A . nigcr (Witteveen et al, 1992). Furthermore, it is known that catalases can be excreted by fungi, cspecially by Penicillia and Aspergilli, in high quantities (Chaga et al, 1992;Nishikawa et al, 1993).…”