Before inoculating the preculture with the first post-sporal Hungate-tube culture, a heat shock was performed at 80 °C for 3.5 min to stimulate the germination of spores. The preculture was then inoculated (10% v/v) and incubated at 35 °C without agitation for 24 h. After the microorganism growth, the reactor was inoculated at 10% (v/v) and the pH was set at 6.2 by the addition of NaOH 3 M.