Bacillus sp. RTS11, a xylanolytic strain, was isolated from the Algerian desert rocks. Genetic analysis revealed a remarkable 98.69% similarity to Bacillus pumilus. We harnessed optimization techniques, including Plackett-Burman screening and Box-Behnken optimization design, to amplify xylanase production and activity. The outcome of these efforts was an optimized medium that yielded an impressive xylanase production titer of 448.89 U, a threefold increase compared to the non-optimized medium (146 U). The Purification of xylanase was achieved through the three-phase partitioning technique, employing t-butanol and various chromatographic methods. Notably, anion exchange chromatography led to isolating a highly pure enzyme with a molecular weight of 60 kDa. The xylanase exhibited its peak activity at a temperature of 60°C and a pH of 9.0. When applied to pulp pretreatment, 20 U/g of xylanase demonstrated a substantial increase in the release of phenolic and chromophore compounds while reducing sugar content in the pulp. Furthermore, this versatile xylanase shows its ability to efficiently hydrolyze a variety of agro-industrial residues, including wheat bran, corn and grape waste, wheat straw, and sugarcane bagasse. These findings underscore the significant potential of this xylanase enzyme in biobleaching processes and the utilization of agro-industrial waste, opening up exciting avenues for sustainable and environmentally friendly industrial applications.

From sand in the Algerian Sahara, an isolated strain of Bacillus called Bacillus sp. SRIT8 showed little chitinase activity when grown in a minimal medium supplemented with chitin (2.36 U). Using Plackett-Burman and Box-Behnken statistical plans, we could maximize chitinase synthesis, which led to a notable increase in this enzymatic activity (112 U). The purification of the resulting enzyme involved three steps: ammonium sulfate precipitation, molecular exclusion chromatography, and anion exchange chromatography. This process yielded a specific activity of 5437.14 U/mg with a purification yield of 22.44%. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis examination revealed a protein band of about 31 kDa, and optimum enzyme activity was found at pH 5 and 40 °C. Enzyme activity was boosted by Ca+2, Na+, and Mn+2 ions but was suppressed by Hg+2 ions. The purified enzyme inhibited the growth of the plant pathogen Fusarium graminearum on wheat in both in vitro tests. So, it might prevent fungal infections in wheat throughout the germination process. The enzyme was also effective as a bioinsecticide, killing up to 52% of the larvae of Sitophilus granarius Linnaeus, an insect pest of stored grain. Our chitinases capacity to hydrolyze fungus cell walls as well as insect cuticles can be utilised as biological control agent.