A lipase-producing strain from Indonesia hot spring, named Bacillus sp. BI-3, was screened by transparent circle. The ranges of single factors(culture temperature, pH, carbon sources, nitrogen sources, metal ions, dosage of NaCl and inoculation amount) were selected by single factor experiment firstly. Then, Box-Behnken design and response surface methodology were adopted to determine the optimal fermentation conditions. The results showed that the optimal fermentation conditions of Bacillus sp. BI-3 were obtained as follows: culture temperature 49.1?℃, peptone 0.78%, SiCl2 13 mmol/L, inoculation amount 1.5%, initial pH 7.0, yeast powder 0.4%. The enzyme activity of fermented supernatant was 224.63 U/mL after optimization. |