[Citric acid biosynthesis by Aspergillus niger strain IM-13 on a nutrient medium with methanol]

The dynamics of citric acid biosynthesis and some morphological changes of Asp. niger IM-13 in culture media containing starch hydrolysate and 3% methanol were traced. The culture developed in filamentous form and little fine pellets. Deformed hyphae with characteristic extensions were observed. The changes in Asp. niger IM-13 metabolism were studied by comparing the biomass accumulation, the utilization of reducing substances, the citric acid biosynthesis, pH and the protein content of the control and the experimental variants. A suppression of growth in the period from the 48th hour of cultivation up to the end of the process, suppression of protein synthesis in the micelium and increased synthesis of citric acid were established.