COMPARATIVE STUDIES OF ALKALINE PROTEASE PRODUCTION IN SOLID STATE FERMENTATION: TRAY BIOREACTOR AND FLASK

Abstract

In this study, production of protease in solid state fermentation using Bacillus licheniformis was
investigated. Fermentation was carried out in batch and semi-bath systems including flask and tray
bioreactor. Wheat bran, rice bran and mixtures of both agro-wastes were used as substrate.
Maximum enzyme production was obtained using wheat bran as sole substrate with high activity of
798.83, 776.91 and 562.11U/gds for top, middle trays and flask, respectively. Results showed that
optimum incubation time of 48h was defined. Enzyme production was evaluated with different
incubating temperatures and initial moisture content of solid substrates. Maximum protease activity
was observed at 35 and 40˚C for the tray bioreactor and flask, respectively. The obtained results
showed that maximum protease production was achieved with substrate initial moisture of 150, 200
and 150% for the flask, top and middle trays, respectively. In addition, the enzyme activity was
improved by supplementary substrate such as corn meal as an inducer, which gave protease
activities of 678, 830 and 940U/gds, for flask, middle and top trays, respectively.