Cost-effective production of Bacillus licheniformis using simple netting bag solid bioreactor

A novel simple solid state fermentation method, netting bag bioreactor (Phi 120 x 800 mm), was developed and used to cultivate Bacillus licheniformis as probiotics. High spore yield (1.2 x 10(11) CFU/g dry substrate) has been obtained by using this method. Comparing to the tray bioreactor and the packed bed bioreactor for Bacillus fermentation, the netting bag method was more cost-effective, time- and space-saving and the material cost is also as low as ca. US $293 per 1,000 kg spores. Thus, netting bag SSF can be widely applied to produce probiotic bacteria in developing areas.