Utilization of gluconate by Aspergillus niger. I. Enzymes of phosphorylating and nonphosphorylating pathways.

Gluconate which was produced in cultures of Aspergillus niger with glucose as the sole source of carbon, or which was added after exhaustion of glucose, was utilized by this mold. In cell-free extracts from gluconate degrading mycelia gluconokinase and five enzymes of the pentose phosphate pathway were identified. Enzymes of the Entner-Doudoroff pathway and of a modified (non-phosphorylating) Entner-Doudoroff system, as well as a gluconate dehydrogenase could not be detected. It is concluded that gluconate after its phosphorylation to 6-phosphogluconate is metabolized via the pentose phosphate pathway by the strain used.