Optimization of culture conditions of a moderately halophilic bacteria by response surface methodology

The culture conditions of a moderately halophilic bacteria strain screened from the surface of bacon were optimized by response surface methodology.Based on single factor tests, Plackett-Burman design was applied to screen key components in culture conditions.Then, the steepest ascent method was adopted to determine the maximum points.Finally, the concentrations of key components were confirmed by central composite deign and response surface methodology.It was showed that salinity, initial pH and culture temperature were key factors.The optimized medium consisted of 10g/L tryptone, 5g/L yeast extract, 54.8g/L NaCl, and the optimized condition consisted of initial pH7.9, culture temperature 32.8℃, liquid volume 70mL in 250mL flask, orbital shaker speed 120r/min.In optimized conditions, the bacteria density expressed by net added value of OD600nm was 3.349±0.021 after 2d, which was 13% higher than before.