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

Abstract

Production of thermostable alkaline protease in tray bioreactor for solid state fermentation is a unique process which may lead to an economical approach for production of enzyme from agricultural waste or low cost substrate. 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 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 (7-13), with maximum activity was defined at 65 ˚C and pH value of 8.