Abstract
The article presents the results of comprehensive studies aimed at improving the efficiency of citric acid recovery from a fermentation broth obtained using the Aspergillus niger R5/4 strain. Particular attention was paid to evaluating the impact of different ozonation regimes, applied at the equipment sterilization stage, on the microbiological purity and stability of the fermentation process. Optimization was carried out for the key stages of the technological process, including neutralization, clarification, evaporation, and crystallization. It was established that ozonation at a concentration of 200 ppm, with a feed rate of 10 g/min and a residual content of 1 ppm, ensured the maximum yield of citric acid, whereas sterilization without ozonation resulted in decreased efficiency. The optimal parameters of subsequent processing stages were identified: neutralization with calcium carbonate (CaCO₃) at a concentration of 75 g/L and 50 °C, as well as clarification at 20 °C with 1.5 h of stirring. The combination of these factors enabled achieving a citric acid yield of 91.6%. The obtained results scientifically substantiate the effectiveness of combining ozonation with subsequent processing stages, providing a practical basis for improving citric acid production at the industrial level. This, in turn, paves the way for the development of new solutions aimed at enhancing the stability and economic efficiency of biotechnological production.