The growing amounts of agricultural residues require sustainable solutions for their use. Here, wheat, rice, barley, and oat straw were evaluated as renewable feedstocks for the enzymatic production of xylooligosaccharides (XOS). Hydrolysis used recombinant xylanase from Bacillus sonorensis T6 under optimized conditions (40 °C, pH 7.0), with stepwise enzyme addition. Subsequently, hydrolysis efficiency was found to vary by substrate, with wheat straw producing the highest reducing sugar yield (up to 40.1 g kg⁻¹), followed by barley, oat, and rice straw. As hydrolysis progressed, the influence of enzyme concentration became less pronounced, suggesting that substrate accessibility and the accumulation of hydrolysis products may increasingly affect the overall hydrolysis efficiency. FTIR, NMR, SEM, and TLC analyses confirmed substantial structural changes in the biomass and the formation of carbohydrate-rich hydrolysis products. TLC analysis indicated the presence of low-degree polymerization oligosaccharides with migration behavior similar to X2 and X3 standards, while FTIR and NMR spectra were consistent with β-(1→4)-linked carbohydrate structures. The xylanase from Bacillus sonorensis T6 hydrolyzed all substrates, revealing broad specificity and suitability for diverse lignocellulosic feedstocks, despite differences in biomass structure. Overall, the results highlight the importance of substrate-dependent factors in enzymatic hydrolysis and demonstrate that xylanase from Bacillus sonorensis T6 converts cereal straw into value-added oligosaccharide-rich products, thereby supporting the development of cost-effective, region-specific biorefinery strategies.

Antibiotic resistance of Mycobacterium tuberculosis poses a serious threat to global health. Kazakhstan is among the top 30 countries with the highest levels of multidrug-resistant tuberculosis and rifampicin-resistant tuberculosis. Existing antibiotics are losing effectiveness due to the rapid growth of drug resistance, which is why DNA repair enzymes of the pathogen are being considered as promising targets for new antibiotics. Unlike many other bacteria, M. tuberculosis lacks the classical mismatch repair system; instead, it employs an alternative pathway mediated by the endonuclease NucS. This article discusses the role of NucS in maintaining genomic stability in M. tuberculosis and its involvement in the development of antibiotic resistance. A review of experimental data shows that inactivation of NucS leads to a hypermutator phenotype, increasing the likelihood of the emergence of drug-resistant strains. These properties make NucS a promising target for antibacterial therapy. The study of NucS as a critically important protein in the pathogenesis and resistance of M. tuberculosis opens new avenues for the development of targeted drugs and strategies to suppress the development of resistance.

Background/Objectives: Multidrug-resistant tuberculosis remains a critical public health challenge in Kazakhstan, yet the genomic determinants contributing to its emergence are still insufficiently understood. Although the quantity of genomic studies from Central Asia and the wider post-Soviet region has increased in recent years, the involvement of DNA repair and genome maintenance pathways in the development of resistance within Kazakhstan has not been comprehensively explored. Methods: In this study, we performed whole-genome analysis of 175 Mycobacterium tuberculosis clinical isolates collected across Kazakhstan between 2010 and 2022 to evaluate the contribution of single-nucleotide polymorphisms in DNA replication, repair, and recombination (3R) genes to the evolution of drug resistance. Results: Alongside well-established resistance mutations in gyrA, we identified recurrent variants in 3R-associated loci (genes involved in DNA replication, repair, and recombination)—including polA, uvrC and ligC—that were enriched among drug-resistant isolates, suggesting a broader role for genome maintenance pathways in facilitating resistance evolution under treatment pressure. Conclusions: These findings provide the first region-specific genomic insights into 3R gene variation in Kazakhstani M. tuberculosis isolates.