Screening, Identification, and Fermentation Conditions Optimization of an Ectoine-producing Strain from the Jintan Salt Cavern

Abstract:

Objective This study aimed to screen high-yield ectoine-producing strains from the strains isolated from the Jintan salt cavern and optimize their culture conditions to enhance ectoine production. Method High-performance liquid chromatography (HPLC) was employed for quantitative analysis and liquid chromatography-mass spectrometry (LC-MS) for qualitative analysis. The ectoine-producing strains were screened. The effects of pH and mass concentrations of KCl, MgSO₄, L-glutamate sodium (MSG), acid-hydrolyzed casein (CA), and NaCl on ectoine production were investigated via a single-factor approach. Response surface methodology was then adopted to establish a mathematical model between ectoine production and key influencing factors (mass concentrations of KCl, acid-hydrolyzed casein, and NaCl). Result A high-yield ectoine-producing strain, DJA10, was successfully screened and identified as Marinobacter through systematic characterization. Under the optimized culture conditions (MgSO₄ 12.0 g/L, L-glutamate sodium 6.8 g/L, NaCl 56.6 g/L, KCl 37.3 g/L, and acid-hydrolyzed casein 10.5 g/L, pH 8.5), the ectoine titer of the strain significantly increased by 134%, from (195.30±2.06) mg/L to (458.51±1.08) mg/L. Conclusion This study successfully screened a high-yield ectoine-producing strain, DJA10, and significantly enhanced its ectoine production through culture condition optimization, providing an excellent microbial resource for the industrial production of ectoine.