Solid-state fermentation of Aspergillus sydowii G12, an approach to produce isocorydine

Isocorydine is an aporphine alkaloid that is mainly produced via chemical synthesis and extracted from plants. Its hydrochloride has been authorized to be a prescription drug for clinical use. This study aims to discover potential alkaloidal metabolites from endophytic fungi associated with the plant. Endophytic fungi were subjected to solid-state fermentation (SSF) to investigate the production of isocorydine. An aporphine alkaloid was obtained from the metabolite of SSF with Aspergillus sydowii G12. Its chemical structure was deduced to be isocorydine according to the spectroscopic data of ESI-MS, ¹H and ¹³C NMR spectroscopy. The fermentation conditions including substrate, fermentation temperature, and time were optimized. As a result, SSF with A. sydowii G12 using potato as substrate at 20 °C for 15 d could produce isocorydine with a high yield of 2.51 ± 0.09 mg/g. This paper is the first to report an approach to producing isocorydine from microorganisms instead of plants.