Thermostable Alkaline Protease Production via Solid State Fermentation in a Tray BioreactorUsing Bacillus licheniformis ATCC 21424

In solid state fermentation using tray bioreactor, several agricultural residues such as rice bran, sugarcane bagasse, wheat bran, barely bran, corn meal and corn husk were used as substrates. Among them, wheat bran was found to be the most suitable substrate with high enzyme activity of 798.83 and 776.91 U/gds for top and middle trays, respectively. Process parameters such as incubation time (48 hours), cabin temperature (35 ?C) and cabin humidity (90%) were optimized. It was found that the desired carbon and nitrogen supplementary sources were rice bran (1%) and corn meal (2%), respectively. The protease was stable in broad temperature range (30-75 ?C) and pH values of 7-13, with maximum activity was defined at 65 ?C and pH value of 8.