金坛盐穴中产四氢嘧啶菌株的筛选、鉴定及发酵条件优化

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

摘要:

目的以金坛盐穴中分离得到的菌株为研究对象，筛选高产四氢嘧啶菌株并优化其培养条件，以提高四氢嘧啶产量。方法采用高效液相色谱仪（HPLC）进行定量分析，液相色谱-质谱联用仪（LC-MS）进行定性分析，筛选产四氢嘧啶的菌株。通过单因素试验考察KCl、MgSO₄、L-谷氨酸钠（MSG）、酸水解酪蛋白（CA）、NaCl质量浓度及pH对四氢嘧啶产量的影响，并利用响应面优化法建立四氢嘧啶产量与关键影响因子（KCl、酸水解酪蛋白、NaCl质量浓度）的数学模型。结果成功筛选获得一株高产四氢嘧啶的菌株DJA10，经分类鉴定确定其为海杆菌属（Marinobacter）菌株。在最优培养条件（MgSO₄ 12.0 g/L、L-谷氨酸钠6.8 g/L、NaCl 56.6 g/L、KCl 37.3 g/L、酸水解酪蛋白10.5 g/L、pH 8.5）下，菌株四氢嘧啶产量由（195.30±2.06） mg/L提升至（458.51±1.08） mg/L，增幅达134%。结论该研究成功筛选出高产四氢嘧啶的菌株DJA10，通过优化培养条件显著提高了四氢嘧啶产量，为四氢嘧啶的工业化生产提供了优质菌种资源。

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.