Pectate lyase (PL) holds significant potential for applications in various industries. However, the existing PL was unable to adapt to thermo-alkaline industrial environments. In this work, a PL from Caldicellulosiruptor bescii DSM 6725 (hereafter, CbPelD) was studied to disclose its structural and biochemical properties. CbPelD consisted of a putative signal peptide sequence, a short linker region, and a catalytic domain (PelD-II), along with an exoacting β-fructofuranosidase domain (PelD-I). In molecular dynamics simulation, PelD-II demonstrated significantly higher activity and thermal stability compared to other truncated enzymes of CbPelD. The optimal pH and temperature for PelD-II were 10.0 and 60 °C, respectively, with the specific activity increasing by 164–223% in the presence of Ca2+ or Ni2+. The exotype PelD-II exhibited efficient degradation of polygalacturonic acid (PGA) into unsaturated galacturonic acid (uG1), digalacturonic acid (uG2), and trigalacturonic acid (uG3). In the bioscouring assay, PelD-II exhibited a significant increase in the wetted fabric area to 6.072 ± 0.684 cm2, which was about 7.9 times higher than untreated fabric. Scanning electron microscopy further revealed that treatment with PelD-II resulted in a smoother fiber surface, providing direct visual confirmation of the enzyme’s action. These results highlight the potential of PelD-II for applications in the textile industries.
Xylanase plays an important role in the hydrolysis of hemicellulose and has gained much attention in the field of biological degumming. The research for xylanases with cellulase-free and high activity for biological degumming has intensified in recent years. In the present research, heterologous expression of a novel endo-β-1,4-xylanase (GH30) from Dickeya dadantii DCE-01 in Escherichia coli BL21 (DE3) was reported. Biochemical characterization of the enzyme and a potential application in ramie biological degumming was discussed. The results showed that the xylanase gene consists of 1251 nucleotides, belonging to glycoside hydrolase family 30 (GH30). The optimal activity of the xylanase was observed at 50℃ and a pH value of 6.4. The Km and Vmax values for beechwood xylan were 14.25 mg/mL and 296.6 μmol/mg, respectively. The catalytic activity was enhanced by addition of 1 mM Cu2+, Ca2+, Mg2+, and K+. The recombinant enzyme was specific for xylan substrates. The enzyme exhibited hydrolytic activity toward ramie hemicellulose. The recombinant xylanase could be effectively applied to ramie degumming.
危险品化学品经营许可证（带存储）