[Isolation, identification and fermentation optimization of Bacillus tequilensis PanD37 producing L-aspartate α- decarboxylase].

ABSTRACT

OBJECTIVE: We screened bacteria producing L-aspartate α-decarboxylase from grapery soil and optimized the fermentation conditions. METHODS: L-aspartate α-decarboxylase producing bacteria were screened by color-changing circle and liquid secondary screening culture media. Combination of morphological, physiological and biochemical characteristics and 16S rRNA sequence analysis were used to identify the bacteria. Fermentation conditions were optimized by single factor test and orthogonal experiment. RESULTS: Strain PanD37 showed high L-aspartate α-decarboxylase producing property and was identified as Bacillus tequilensis. The optimum fermentation conditions of PanD37 were liquid volume of 50 mL in 500 mL flask, 220 r/min at 35 °C, inoculation amount of 5% for 28 h with a medium of 22.5 g/L sucrose, 7.5 g/L fumaric acid, 20 g/L peptone, 6 g/L L-aspartic acid, 2 g/L Triton X-100, at initial pH of 7.0. Under the optimal fermentation conditions, the highest L-aspartate α-decarboxylase activity reached 44.57 U/mL, which was 2.57 folds higher than that obtained before optimization. CONCLUSION: Strain PanD37 was identified as Bacillus tequilensiswhich was capable of highly producing L-aspartate α-decarboxylase under the optimal fermentation conditions.