Response surface statistical optimization of fermentation parameters for resveratrol production by the endophytic fungus Arcopilus aureus and its tyrosinase inhibitory activity

The present investigation primarily focusses on enhancement of resveratrol production by endophytic production from the endophytic fungus, Arcopilus aureus via one variable at a time approach (OVAT) followed by statistical approach using response surface methodology (RSM). The paper also highlights the characterization of fungal resveratrol using spectroscopic techniques. Further the tyrosinase inhibitory property was also explored in this communication for its possible use as a cosmeceutical ingredient. Optimization of physicochemical and nutritional parameters using OVAT approach exhibited 1.23-fold enhancement in production of resveratrol when compared to initial yield, 89.1 ± 0.08 µg/mL. Further RSM resulted in 1.49-fold enhancement in resveratrol production i.e. 133.53 µg/ml. Further, 25 mg of fungal resveratrol in pure form was obtained from the spent broth of Arcopilus aureus by column chromatography using a mobile phase comprising of MeOH: DCM in a ratio of 1.75:98.25. Further its purity on TLC was checked using 5% MeOH: DCM as mobile phase. Symmetrical peak with Rt of 3.36 min using a C18 reverse phase column confirmed the homogeneity of the purified fungal resveratrol with standard resveratrol and further corroborated by 1H-NMR, 13C-NMR and HR-MS analysis. Fungal resveratrol exhibited a good tyrosinase inhibition with an IC50 of 2.654 ± 0.432 µg/mL as compared to Kojic acid (1.329 ± 0.333). The present study has provided sufficient lead that process optimization techniques can complement each other for optimized production of bioactive compounds by microorganisms apart from strain improvement techniques which are generally adopted in the industry. The enhancement of resveratrol production by Arcopilus aureus by process optimization further opens up avenues for strain improvement for commercial resveratrol production through fermentation for nutraceutical and cosmeceutical applications.