Respiratory pathways and oxygen toxicity inPhanerochaete chrysosporium

Abstract

Phanerochaete chrysosporium maintained on glucose as the carbon source contained severely impaired mitochondria that were characterised by the loss of both succinate dehydrogenase and cytochrome oxidase activities. These cells maintained a constant value for energy charge using anaerobic metabolism. Cells with these properties express lignin peroxidase when supplied with a pure oxygen atmosphere, which may reflect a response to accumulating reactive oxygen species. Cells maintained on cellulose retained fully functional mitochondria, but expressed lignin peroxidase without being exposed to a pure oxygen atmosphere. In the cells maintained on cellulose, mitochondrial function may be limited by the supply of glucose, leading to the accumulation of reactive oxygen species.

Effect of a perfluorocarbon‐Pluronic F 68‐based emulsion on a Phanerochaete chrysosporium biofilm immobilised in a membrane gradostat bioreactor

“…[8 -11] However, prolonged exposure to high partial oxygen pressures in any cell culture leads to oxygen toxicity resulting from an increased generation of ROS, a consequence that does not bode well for prolonged MGR operation. When the fungus was maintained on a glucose-based medium while, simultaneously being exposed to high partial pressures of oxygen, the functioning of mitochondria was impaired, [12] due to the loss of both succinate dehydrogenase and cytochrome oxidase activities. Furthermore, continuous oxygenation was shown to have negligible effects on the increments in DO penetration depth in P. chrysosporium biofilms.…”