Abstract:In this work, response surface methodology was used to optimize the fermentation medium components of E. cristatum FS-10 producing antibacterial active substances. Meanwhile, the antibacterial activity products were isolated and preliminary identification through highperformance liquid chromatography (HPLC), matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and Fourier transform infrared (FT-IR) spectrometry. The results showed that the optimal medium components were determined as follows: anhydrous glucose (carbon source) 7.5%, sodium nitrate (nitrogen source) 0.65%, and potassium chloride 4.5%. Under the optimized fermentation conditions, the bacteriostasis rate reached 54.4% against the suspension of Psychrophile bacteria(1×105 CFU/mL). Two antibacterial active components(FS-IV and FS-VI) were isolated and identified. The molecular mass of component FS-IV and FS-VI were 1 630.8 u and 840.5 u, respectively, which might imply the existence of heteropolysaccharide derivative compounds and amide derivative compounds. Antibacterial compounds could inhibit the growth of some foodborne bacteria, including Pseudomonas, Shewanella and Psychrophile. They were stable to heat and acid-base conditions.