A novel structured bioreactor for solid-state fermentation

A novel patented solid-state bioreactor (251 L) with honeycomb loading device was designed and its performance was tested. First, this apparatus gave a 66.87 % of calculated loading coefficient (volume ratio), which was almost twofold compared with conventional fermenters. Next, considering the crucial effect of heat transfer on bed loading and microbial growth, the performance was validated by temperature variance during fermentation and spore viability of Bacillus cereus DM423. Air pressure pulsation or external water jacket was used to control temperature; the maximal temperature variation was 7.7 versus 19.8 °C, respectively during fermentation. The difference was mainly due to the continuous gas phase characterized by solid-state fermentation (SSF). The average living spores of (1.50 ± 0.07) × 1011 cfu/g at 40 h obtained from the device was higher than (0.70 ± 0.03) × 1011 cfu/g from flask at 48 h. The results indicated that this new loading bioreactor with air pressure pulsation could be a good prospect for industrialization of SSF employing bacterial cultures.