Optimization and Scale up of Cellulase free Endo xylanase Production by Solid State Fermentation on Corn cob and by Immobilized Cells of a Thermotolerant Bacterial Isolate

Different agro-residues were evaluated as substrates in solid state fermentation for xylanase production by a thermotolerent Bacillus isolate. Various fermentation parameters were optimized for enhanced endoxylanase production under solid state fermentation (SSF). Maximum enzyme production of 74.96±5.2 U/gds took place at 45°C with corn cob (CC) and mineral salt solution (MSS) after 72 h, at pH 6.0 and particle size of 500 μm. A ratio of substrate: moistening agent of 1:2.5 was found to be optimum for CC, a solid substrate rarely utilized for bacterial xylanase in SSF. Continuous xylanase production by recycling immobilized cells could be achieved till 10 cycles with maximum enhancement of 156.05% and 219.21% after 5 and 4 cycles in static and submerged states respectively. Scale up in large trays under SSF yielded 157.12 ± 8.7U/gds in static state and 111.47± 8.1U/gds at 110 rpm.