A modified mineral medium was used in the fermentation in the
bioreactor containing (g/L): Na2HPO4·2H2O 1.2, KH2PO4 4,
MgSO4.7H2O 2, (NH4)2SO4 2, yeast extract 1 and trace
element solution 2 ml. The carbon sources were sterilized
separately at 121 °C for 20 min and then aseptically added
into the flask containing the other components at room
temperature. The pH of the final culture medium was
adjusted to 7.0 before bacterial inoculation.