Cloning, overexpression and characterization of a thermostable endo-1,4-beta-xylanase from Anoxybacillus vranjensis ST4

This research deals with the characterization of a thermostable endo-1,4-beta-xylanase enzyme from Anoxybacillus vranjensis ST4, a thermophilic bacterium isolated from Vranjska Banja hot spring, Serbia. The enzyme shows a high degree of identity with the same type of enzyme from other species of the genera Anoxybacillus (97%), Geobacillus (74%) and Paenibacillus (65%). The gene for endo-1,4-beta-xylanase from the thermophilic strain ST4 was cloned into the pQE_Ek expression vector and successfully expressed and purified from the Escherichia coli M15[pREP4]. The study encompasses recombinant production, purification, and the comprehensive characterization of the enzymatic properties of endo-1,4-beta-xylanase. This is the first successful overexpression, purification and characterization of a recombinant thermostable endo-1,4-beta-xylanase enzyme from Anoxybacillus. With a monomeric structure of 38.7 kDa, the enzyme demonstrates peak activity at 70°C and pH 6.5. Notably, it exhibits remarkable stability across a wide pH range and at high temperatures, rendering it suitable for diverse industrial applications. Investigation into the enzyme’s kinetic parameters, substrate specificity, and its ability to degrade xylan into high-energy value products further enhances understanding of its biotechnological potential. These findings underscore the significance of thermophilic bacteria and their thermostable enzymes in various industrial processes.