Rapid enzyme production and mycelial growth in solid-state fermentation using the non-airflow box.

Solid-state fermentation (SSF) has become an attractive alternative to submerged fermentation (SMF) for the production of enzymes, organic acids, and secondary metabolites, while there are many problems during the culture of SSF. We recently created a SSF system using a non-airflow box (NAB) in order to resolve the problems, which enabled the uniform culture in the whole substrate and high yield of many enzymes. In this paper, further characterization of SSF using the NAB was carried out to obtain other advantages. The NAB culture under the fixed environmental condition exhibited a rapid increase in enzyme production at earlier phase during the culture compared with conventional SSF. Total mycelial growth also exhibited the same trend as enzyme production. Thus, the increase in the rate of the enzyme production was thought to mainly be attributed to that of the growth. To support it, it was suggested that the NAB culture resulted in most optimal water activity for the growth just at the log phase. In addition, the NAB culture was able to achieve high reproducibility of enzyme production, derived from uniform condition of the substrate during the culture. The results indicate that the NAB culture has many benefits for SSF.