Biopesticidal Potential and Fermentation Media Optimization of Epicoccum sp. Strain BPF3, an Endophytic Fungus Isolated from Bethencourtia palmensis

Endophytic fungi are an important source of bioactive compounds with potential applications in sustainable pest management. In this study, we isolated an Epicoccum species from Bethencourtia palmensis, an endemic plant from the Canary Islands, and performed bioactivity-guided fractionation of its ethyl acetate extract. The extract exhibited significant bioactivity against several agricultural pests, including Myzus persicae, Spodoptera littoralis, Botrytis cinerea, Dickeya dadantii and Pseudomonas syringae, and against the tick Rhipicephalus bursa. After bioguided fractionation, the major constituent of the extract and responsible for most of its bioactivity was identified as 2,3-dihydro-2-hydroxy-2,4-dimethyl-5-trans-propenylfuran-3-one (BPF3-1). Its structure was elucidated by 1D and 2D NMR experiments and high-resolution electrospray ionization mass spectrometry (HRESIMS) data analysis, and its absolute configuration was established by comparison of experimental and calculated electronic circular dichroism (ECD) spectra. This is the first report of BPF3-1 production by an Epicoccum species and the first documentation of its insect antifeedant and acaricidal activities. The culture medium was subsequently optimized preliminarily to enhance BPF3-1 production. Maximum production was achieved using a medium supplemented with fructose and mycological peptone with a 4.88-fold increase in production over the control, and this formulation was selected for an initial fermentation scale-up in a bench-top bioreactor. Under these conditions, the maximum BPF3-1 concentration was reached three days earlier than in flask cultures, providing an initial basis for further process development.