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

الملخص EN

Different agro-residues were evaluated as substrates in solid state fermentation for xylenes 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 450C 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 xylenes in SSF.

Continuous xylenes 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.