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.