A novel thermostable xylanase of Paenibacillus macerans IIPSP3 isolated from the termite gut.

Xylanase is an enzyme in high demand for various industrial applications, such as those in the biofuel and pulp and paper fields. In this study, xylanase-producing microbes were isolated from the gut of the wood-feeding termite at 50°C. The isolated microbe produced thermostable xylanase that was active over a broad range of temperatures (40-90°C) and pH (3.5-9.5), with optimum activity (4,170 ± 23.5 U mg⁻¹) at 60°C and pH 4.5. The enzyme was purified using a strong cation exchanger and gel filtration chromatography, revealing that the protein has a molecular mass of 205 kDa and calculated pI of 5.38. The half-life of xylanase was 6 h at 60°C and 2 h at 90°C. The isolated thermostable xylanase differed from other xylanases reported to date in terms of size, structure, and mode of action. The novelty of this enzyme lies in its high specific activity and stability at broad ranges of temperature and pH. These properties suggest that this enzyme could be utilized in bioethanol production as well as in the paper and pulp industry.