H-NMR-based metabolomics profiling of Beauveria bassiana on different growth media for the determination of its secondary metabolites / Nur Amirah Khirul Anuar ... [et al.]

The entomopathogenic fungus (EPF) Beauveria bassiana is commercially used as a microbial insecticide against agricultural pests. Some strains of B. bassiana protect crops from pathogens. B. bassiana produces bioactive secondary metabolites (SMs) with potential applications. The present study aims to monitor the growth and behaviour of B. bassiana in different growth media and the effect of different growth media on the production of SMs. The fungal culture was recultivated and then inoculated in broth and agar growth media to perform this study. After 12 days of incubation of B. bassiana in potato dextrose broth (PDB) and a specific medium at temperatures between 28 - 30℃, SMs were extracted from broth cultures using liquid-liquid extraction. To harvest the SMs, the broth media of each culture was extracted using ethyl acetate. After the evaporation of the ethyl acetate using a rotary evaporator, the crude extracts were obtained. The crude extracts were then subjected to 1 H-NMR and 2D HSQC analysis using a 600 MHz NMR spectrometer to monitor the presence of different SMs in the crude extracts. The analysis revealed that different types of SMs were produced by B. bassiana under different media and conditions. However, some SMs were detected in the 1 HNMR spectrum of the PDB extract that was completely absent in specific Fingal medium, further confirmed by the 2D HSQC experiment. In conclusion, this study revealed that modifying the media constituents and conditions, such as variable temperatures, could produce different SMs, as predicted by the NMR analysis.