Production of polygalacturonases by Aspergillus oryzae in stirred tank and internal- and external-loop airlift reactors

► The production of polygalacturonases (PG) was evaluated in bioreactors. ► The intensity of cell growth and variation in pH influenced the production of PG. ► Satisfactory results were obtained by utilization of airlift bioreactors. ► The airlift bioreactors showed lower costs of installation and operation.