| Halophile developed a unique metabolic mechanism during the long process of evolution owing to high-salt living environment, and produced secondary metabolites with novel structures. These secondary metabolites may have potential value of application in bio-environmental protection, food, pharmaceutical, fermentation industry and agricultural production.In this study, four endophytic fungus, Salicorn-3,5,8 and 19, were isolated and identified from Salicornia bigelovii which was collected from XiangShui, Yancheng city, Jiangsu Province in China. The 18S rDNA and ITS1-5.8S-ITS4 rDNA region of these two strains were amplified by Polyrnerase chain reaction (PCR) after extraction of mycelia genomic DNA, the homology were analysed after being sequenced. The phylogenetic tree was generated based on the sequences of the 18S rDNA and internal transcribed spacer (ITS) region, combined with morphological observation, these four strains were identified as Phoma betae, Fusarium sp., Gibberella avenacea and Cunninghamella sp.The fermentation conditions of Salicorn-19 were optimized by using the Plackett-Burman, the steepest hill-climbing experiment and the response surface method, to maximize its antioxidant activity using DPPH free radical scavenger activity guide-assay, The optimum medium was as follows:yeast extract 1.6%, peptone 1.7%, potatoes 30%, maltose 3%,3% mannitol, glucose 0.5%, monosodium glutamate 1.0%, sodium chloride 1%, pH 7. Using the optimum culture medium, the maximum DPPH free radical scavenging rate of the fermentation products was 78.25%, which was significantly higher than before (66.55%).The fermentation products of Salicorn-19 were extracted using cyclohexane after fermentation, three compounds were obtained by silica gel column chromatography, and their structures were elucidated as oleic acid, and linoleic acid and 1,2 oleic acid diglyceride on the base of nuclear magnetic resonance (NMR) and mass spectrometry (MS) analysis. |
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