Xyloglucan Oligosaccharides Hydrolysis by Exo-Acting Glycoside Hydrolases from Hyperthermophilic Microorganism Saccharolobus solfataricus

In the field of biocatalysis and the development of a bio-based economy, hemicellulases have attracted great interest for various applications in industrial processes. However, the study of the catalytic activity of the lignocellulose-degrading enzymes needs to be improved to achieve the efficient hydrolysis of plant biomasses. In this framework, hemicellulases from hyperthermophilic archaea show interesting features as biocatalysts and provide many advantages in industrial applications thanks to their stability in the harsh conditions encountered during the pretreatment process. However, the hemicellulases from archaea are less studied compared to their bacterial counterpart, and the activity of most of them has been barely tested on natural substrates. Here, we investigated the hydrolysis of xyloglucan oligosaccharides from two different plants by using, both synergistically and individually, three glycoside hydrolases from Saccharolobus solfataricus: a GH1 β-gluco-/β-galactosidase, a α-fucosidase belonging to GH29, and a α-xylosidase from GH31. The results showed that the three enzymes were able to release monosaccharides from xyloglucan oligosaccharides after incubation at 65 °C. The concerted actions of β-gluco-/β-galactosidase and the α-xylosidase on both xyloglucan oligosaccharides have been observed, while the α-fucosidase was capable of releasing all α-linked fucose units from xyloglucan from apple pomace, representing the first GH29 enzyme belonging to subfamily A that is active on xyloglucan.

Preparation and characterization of a new mutant homolog of chemotaxis protein CheY from anaerobic hyperthermophilic microorganism Thermotoga naphthophila

Using genetic engineering methods the expression vectors structures have been designed to produce recombinant proteins TnaCheY and Tna CheY-mut, the homologues of the chemotaxis protein CheY from the hyperthermophilic organism Thermotoga naphthophila in Escherichia coli BL21(DE3) cells. The cultivation conditions of transformed strains were optimized. The influence of episomal expression of the heterologous chemotaxis protein CheY on growth kinetics parameters of the culture of mesophilic bacteria E. coli was studied. The optimal purification flowchart of the obtained proteins using thermolysis is proposed. Using the E. coli BL21(DE3) laboratory strain as an example, the possibility of employment the episomal expression of such proteins to control the cultivation and production time of pharmaceutically and industrially valuable metabolites due to the impact on some stages of the bacterial chemotaxis is experimentally proved.