A promising approach for improved citric acid production by Aspergillusniger with the assistance of cinnamaldehyde derivatives.

Considering the importance of food preservation, this study presents the synthesis of cinnamaldehyde derivatives i.e., chalcones and pyrazoles with an atom economy of >92 % using an energy-efficient and eco-friendly microwave-assisted synthesis with high purity and yield. All the compounds were evaluated for their ability to enhance the growth of Aspergillus niger for citric acid production via submerged fermentation, which showed that the pyrazoles significantly outperformed both untreated samples and chalcones in citric acid production, with enhancements of up to 25-times and 4-times, respectively. Compounds at lower concentrations yielded citric acid levels of 100-113 g/L. The purity and authenticity of citric acid recovered were confirmed through spectral studies. Molecular docking against aconitase enzyme from nine different sources revealed various types of interactions with binding affinities ranging from -7.2 to -10. The target compounds can be regarded as valuable "lead compounds" for citric acid production, effectively addressing both demand and supply.