Pilot-Scale Gas Double-Dynamic Solid-State Fermentation for the Production of Industrial Enzymes

Presently, the modern solid-state fermentation (SSF) industry remains traditional; there are few designs available for bioreactors operating in SSF on a large scale, which is mainly caused by the problems in engineering that appear when scaling up this technique. Gas double-dynamic solid-state fermentation (GDD-SSF) technology has been proven available in industrial production of biopesticide. However, there are few other examples using the GDD-SSF technology in other fermentation industries. To test its applicability in other fermentation industries, the self-made pilot-scale bioreactor for GDD-SSF of 800 L was used for the production of various typical enzymes. The comparing effects of liquid-solid ratio and air pressure on enzyme production in different fermentation modes were investigated. Results showed that GDD-SSF offered greater advantages to the static SSF in industrial enzyme preparation, such as pectinase, glucoamylase, protease, and cellulase. It could not only improve enzyme activities with a largest increase reached 2.84 times but also shorten the fermentation period. Furthermore, decreased temperature gradient was found in GDD-SSF, which is crucial for online controlling in industry production. Thus, the necessary and successful pilot-scale fermentation of various enzymes was a rational indication of applicability to large-scale SSF by GDD-SSF.