Porosity changes during packed bed solid-state fermentation

Porosity is one of the key parameters in a typical solid-state fermentation model that represents the intra and inter-particle void spaces in bioreactor bed. In this research, the particle density and moisture content of the bed were used to determine the porosity changes of the solid substrate bed during the fermentation of Aspergillus niger in a laboratory scale packed-bed bioreactor. Biomass growth was also monitored by means of measuring CO2 and O2 in the bioreactors outlet gas online. As such, an experimental relationship between humidity and porosity has been developed and can be used in solid-state fermentation modeling.