ABSTRACT
The medium is an important factor to be taken into account following two considerations—as substrate, it has to efficiently cater to microbial nutritional needs and as a support of the culture, it has to possess favorable physical properties. The solid medium becomes compacted or creates air channeling, leading to a system with inefficient heat and mass transfers. The increased production of many induced enzymes using solid-state fermentation is related to a significant resistance of organisms cultivated in a solid medium to catabolic repression. Many studies have been published in recent years supporting the application of Solid-State Fermentation in valorization of agricultural byproducts and in production of fine chemicals and enzymes. A spouted bed requires a lower gas-flow rate and may provide good mass and heat transfer for solid materials that are too coarse or dense for stable fluidization.
