| In order to improve the ability of alginate degradable Cobetia sp.20 strain to produce alginate lyase, its fermentation medium was optimized by response surface methodology. Firstly, single factor method was used to explore the effects of different carbon sources, different nitrogen sources, the addition amounts of carbon source, nitrogen source, sodium chloride, potassium dihydrogen phosphate, and ferrous sulfate, as well as pH in fermentation medium on the production of alginate lyase. Based on single factor test and Plackett-Burman test, the main factors affecting the enzyme production of Cobetia sp.20 were determined. The regression equation was established by response surface test, and the results showed that the optimal fermentation medium and conditions for Cobetia sp.20 were as follows: 15.00 g/L sodium alginate, 7.50 g/L ammonium sulfate, 15.00 g/L sodium chloride, 0.50 g/L magnesium sulfate, 5.30 g/L potassium dihydrogen phosphate, 0.01 g/L ferrous sulfate, and pH 7.58. The optimized enzyme activity was 142.79 U/mL, 23.36% higher than that before optimization. After optimization, the activity of alginate lyase produced by Cobetia sp.20 increased significantly, which laid a foundation for the industrial production of alginate lyase. |
