Identification, optimisation and production of xylooligosaccharides by heat-tolerant xylanase-producing strain

A novel heat-resistant xylanase-producing strain (Thermomyces dupontii J22) isolated from a soil sample in China can produce a high level of cellulase-free xylanase (768.32 U/mL). The conditions for xylanase production by liquid fermentation were optimised through the implementation of single factor experiments and a response surface experiment. The highest xylanase production was obtained when corn cob was added at a 5% concentration as carbon source, yeast paste, tryptone and ammonium dihydrogen phosphate (3:1:1) were added at a total concentration of 3% as nitrogen source, the initial pH was 7.2 and the temperature was 47.5 ℃. The crude enzyme exhibited the highest activity for xylanase at 80 degrees Celsius and pH 6. The crude enzyme was employed in the enzymatic production of xylooligosaccharides (XOS) from hydrothermal extracts of corn cobs, with the optimum reaction temperature and pH identified as 60 ℃ and 7.0, respectively. The final XOS is primarily constituted of xylobiose and xylotriose, representing up to 74.29% of the total composition.