A Preliminary Study On Secondary Metabolites Of A Halotolerant Fungus

Halotolerant fungi is a group of extremophiles, they have unique gene type, special physiological mechanism and special metabolites. The secondary metabolites of halotolerant fungi have very important study and application value. In recent years, more and more researches focus on the secondary metabolites of halotolerant fungi. The researchers isolated many new compounds, which have antitumor or antibacterial activity, from the secondary metabolites of halotolerant fungi. At the same time many studies have suggested that salt stress can change chemical diversity of the secondary metabolites from halotolerant fungi.In order to explore the diversity and novelty of secondary metabolites from fungi in high salt environment. we selected8halotolerant fungi isolated from Kunming salt mine as research materials. First of all, these8halotolerant fungi were fermented in the potato dextrose broth with different salt concentration (0%NaCl,3%NaCl,10%NaCl,2%NaBr). Then,5strains with abundant metabolites diversities were selected to re-screen based on the TLC patterns and diverse morphology under different salt concentration. Metabolites of10L liquid fermentation from selected5strains were fractioned by silica gel column chromatography and Sephedex LH-20gel column chromatography respectively. After the analysis of the extracts by TLC and HPLC, the strain4-92, which may produce novel and bioactive compounds, was choosen. After optimization of fermentation conditions, the target strain was fermented for60L and200L in PDB and PDB with15%NaCl respectively. By means of chromatography over silica gel column, Sephadex LH20, TLC and HPLC,35compounds were isolated from the whole crude extracts.18compounds were obtained and identified,3of them are new products.2new compounds and11known ones were isolated and identified from the extracts of the liquid fermentation of4-92under15%NaCl.1new compound and4known ones were isolated and identified from the extracts of the liquid fermentation of4-92under0%NaCl.