Extraction and characterization of cyclic lipopeptides with antifungal and antioxidant activities from Bacillus amyloliquefaciens.

Abstract

This study aimed to isolate active substances from metabolites of Bacillus amyloliquefaciens SJ100001 and examine their antifungal activity against Fusarium oxysporum (F. oxysporum) SJ300024 screened from the root-soil of cucumber wilt. An active substance, anti-SJ300024, was obtained from the fermentation broth of strain SJ100001 by reversed-phase silica gel and gel chromatography, and further got its chemical structure as cyclic lipopeptide Epichlicin through nuclear magnetic resonance (NMR) and mass spectrometry (MS). In vitro experiments showed that Epichlicin had a better inhibitory rate (67.46%) against the strain SJ300024 than the commercially available fungicide hymexazol (45.10%) at the same concentration. The MTT assays proved that Epichlicin was non-cytotoxic, besides it also had good free radical scavenging ability and total reducing ability. Epichlicin isolated from strain SJ100001 can effectively control F. oxysporum SJ300024 screened from the root-soil of cucumber wilt. Epichlicin may be used as an environmentally friendly and efficient biocontrol agent for controlling Fusarium wilt of cucumber and reducing crop losses. More importantly, the non-cytotoxicity of Epichlicin can avoid harm to consumers. Additionally, Epichlicin has broad application prospects in medicine due to its antioxidant properties.