Keratinase can specifically attack disulfide bridges in keratin to convert them from complex to simplified forms. Keratinase thermal stability has drawn attention to various biotechnological industries. In this study, a keratinase DgeKer was identified from a slightly thermophilic species, D. geothermalis. The in silico analysis showed that DgeKer is composed of signal peptide, N-terminal propeptide, mature domain, and C-terminal extension. DgeKer and its C-terminal extension-truncated enzyme (DgeKer-C) were cloned and expressed in E. coli. The purified DgeKer and DgeKer-C showed maximum activity at 70 °C and pH 9–The thermal stability assay (60 °C) showed that the half-life value of DgeKer and DgeKer-C were 103.45 min and 169.10 min, respectively. DgeKer and DgeKer-C were stable at the range of pH from 9 to 11 and showed good tolerance to some metal ions, surfactants and organic solvent. Furthermore, DgeKer could degrade feathers at 70 °C for 60 min. However, the medium became turbid with obvious softening of barbules after being treated with DgeKer-C, which might be due to C-terminal extension. In summary, a thermostable keratinase DgeKer with high efficiency degradation of feathers may have great potential in industry.

Waste oil pollution and the treatment of oily waste present a challenge, and the exploitation of microbial resources is a safe and efficient method to resolve these problems. Lipase-producing microorganisms can directly degrade waste oil and promote the degradation of oily waste and, therefore, have very significant research and application value. The isolation of efficient oil-degrading strains is of great practical significance in research into microbial remediation in oil-contaminated environments and for the enrichment of the microbial lipase resource library. In this study, Acinetobacter junii WCO-9, an efficient oil-degrading bacterium, was isolated from an oil-contaminated soil using olive oil as the sole carbon source, and its enzyme activity of ρ-nitrophenyl decanoate (ρ-NPD) decomposition was 3000 U/L. The WCO-9 strain could degrade a variety of edible oils, and its degradation capability was significantly better than that of the control strain, A junii ATCC 17908. Comparative pan-genome and lipid degradation pathway analyses indicated that A. junii isolated from the same environment shared a similar set of core genes and that the species accumulated more specific genes that facilitated resistance to environmental stresses under different environmental conditions. WCO-9 has accumulated a complete set of oil metabolism genes under a long-term oil-contamination environment, and the compact arrangement of abundant lipase and lipase chaperones has further strengthened the ability of the strain to survive in such environments. This is the main reason why WCO-9 is able to degrade oil significantly more effectively than ATCC 17908. In addition, WCO-9 possesses a specific lipase that is not found in homologous strains. In summary, A. junii WCO-9, with a complete triglyceride degradation pathway and the specific lipase gene, has great potential in environmental remediation and lipase for industry.

Biotechnological research and application of microbial enzyme production have consistently been focal points for scientific inquiry and industrial advancement. In this study, Bacillus subtilis Y4X3 was isolated from saline–alkaline soil in Xinjiang, China. Extracellular enzyme production analysis revealed that B. subtilis Y4X3 can secrete various enzymes, including cellulase, xylanase, protease, and amylase. Sequencing and assembly of the complete genome of this strain revealed a genome size of 4,215,636 bp with 43.51% C + G content, including 4438 coding genes. Genome annotation was performed with databases to predict gene functions in B. subtilis Y4X3, and a variety of genes related to carbohydrate metabolism were identified. A cellulase-encoding gene was subsequently cloned from the genome and heterologously expressed in Escherichia coli. The optimum pH and temperature for the purified cellulase Cel5A were 5.0 and 60 °C, respectively. Stability analysis revealed that Cel5A remained stable at pH 5.0–9.0 and 20–60 °C; after 1 h at pH 9.0, the relative enzyme activity still exceeded 60%. Additionally, Cel5A was positively affected by various metal ions and exhibited good tolerance to multiple chemical reagents. The results indicate that B. subtilis Y4X3 has the potential to produce a variety of industrial enzymes and could serve as a promising candidate for more efficient and cost-effective industrial applications; the characterized thermostable and alkali-resistant cellulase Cel5A also has potential applications in biotechnology and industry.

EPSP synthase is the target enzyme of glyphosate herbicides. Due to the extensive use of glyphosate, it is very important to obtain EPSPS genes with high glyphosate resistance for the development of transgenic crops. GR79-EPSPS is a class I EPSP synthase with certain glyphosate resistance isolated from glyphosate-contaminated soil. After more than 1000 generations, a Y40I substitution was identified, and the enzyme had a nearly 1.8-fold decrease in Km [PEP] and a 1.7-fold increase in Ki[glyphosate] compared to the wild-type enzyme. Enzyme dynamics and molecular dynamics analysis showed that the substitution was near the hinge region of EPSPS, and the affinity of glyphosate binding to amino acid residues of the active site decreased due to Y40I substitution, resulting in an increase in glyphosate resistance. These results provide more evidence for the combination of directed evolution and rational design of protein engineering.

Salt stress adversely impacts plant physiology by causing ionic, osmotic, and oxidative stress, ultimately hindering growth and yield. The genus Deinococcus contains unique stress resistance genes, and previous studies have shown that proteins such as IrrE, Csp, and WHy enhance stress tolerance in plants and microbial cells. However, their role in Brassica napus L. (oilseed rape) remains unexamined. In this study, a synthetic stress-resistance module, DICW, was constructed using the Deinococcus-derived genes IrrE, Csp, and WHy and heterologously overexpressed in B. napus to assess its impact on salt tolerance. The results demonstrated that the DICW module significantly improved seed germination and seedling growth under salt stress. Transgenic B. napus plants exhibited reduced membrane damage, higher leaf relative water content, enhanced accumulation of osmoregulatory substances, and elevated antioxidant enzyme activity compared to wild-type plants. Additionally, qRT-PCR analysis revealed the upregulation of stress-related genes (BnRD29A, BnP5CS, BnKIN1, BnLEA1, BnNHX1, and BnSOS1) and antioxidant enzyme-related genes (BnSOD, BnPOD, and BnCAT) in transgenic lines. In conclusion, the DICW module plays a crucial role in enhancing salt tolerance in B. napus by regulating stress responses and antioxidant mechanisms. This study provides valuable molecular insights into improving the survival and growth of B. napus in saline environments.