The modular stellarator Wendelstein 7-X in Greifswald, Germany, is currently in the state of commissioning. The sophisticated superconducting magnet system with 50 non-planar and 10 planar coils will be operated at 4K and has to sustain high electromagnetic loads. The likewise quite complex cryostat comprises the outer vessel, plasma vessel, and 254 ports of different types connecting the plasma and outer vessels.The magnet and cryostat systems are instrumented with more than 800 strain gauges, distance, and contact sensors. Implementation and expected results of this extended mechanical instrumentation is the scope of this paper.

Analysis of the structure of two-domain laccase ScaSL from Streptomyces carpinensis VKM Ac-1300 (with a middle-redox potential) revealed determinants that could affect the increased potential of ScaSL. Site-directed mutagenesis of the ScaSL laccase was carried out, and mutants H286A, H286T, H286W, and F232Y/F233Y were obtained. Replacement of His 286 with Ala led to a decrease in redox potential (0.45 V) and an increase in stability at pH 9 and 11; replacement with Thr led to an increase in redox potential (0.51 V) but to a decrease in the thermal stability of the protein; replacement with Trp did not affect the enzyme properties. Replacement of Phe residues 232 and 233 with Tyr led to a shift in enzyme activity to the acidic pH range without changing the redox potential and a decrease in the thermostability and pH stability of the enzyme. All mutants more efficiently oxidized phenolic substrate 2,6-DMP and were able to participate in direct electron transfer (DET) with MWCNT-modified electrodes. The F232Y/F233/Y mutant was unable to degrade triphenylmethane dyes without a mediator but showed a greater degree of decolorization of azo dyes in the presence of the mediator. The crystal structure of laccase with the highest potential was determined with high resolution.

Progress in the field of modern heterogeneous catalysts requires the development of composite materials with a well-developed surface area and sorption capacity, as well as the possibility of functionalization in a specific direction. This paper presents the results of electrochemical synthesis of composites based on an organosilica matrix and multi-walled carbon nanotubes for subsequent application as a platform for enzyme immobilization. By potentiostatic electrodeposition, composite coatings based on two types of organosilica sol (STP_EG and ST_EG) were applied to the surface of a glassy carbon electrode with the addition of MWCNTs subjected to various methods of oxidative treatment. Optimization of the deposition time in the range of 0.5–5 min revealed that the maximum electrochemical activity and heterogeneous transfer rate constants were achieved at 1 min of electrodeposition. It has been found that the use of MWCNTs oxidized in H₂O₂ vapors provides the best balance between hydrophilicity, conductivity, and the formation of a permeable matrix due to fewer defects and carboxyl groups. It has been demonstrated that the selected OP-SG/1 composite effectively supports mediator bioelectrocatalysis with recombinant laccase ScaSL in the presence of an ABTS mediator, as evidenced by the formation of sigmoidal CVs of catalytic oxygen reduction. The obtained results confirm that the electrodeposited organosilica composite is a promising and biocompatible material for the development of surface biocatalysts, which can be used in wastewater treatment technologies and bioreactor design.

A novel two-domain small laccasefrom Streptomyces ochraceiscleroticus (SoSL) was produced through recombination in Escherichia coli and purified by affinity chromatography. The properties (thermal optimum and thermostability, pH optima and pH-stability), kinetic characteristics, substrate specificity and dye decolorization ability were estimated. Laccase SoSL was able to oxidize 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS)and 2,6-dimethoxyphenol (2,6-DMP) with at a maximal rate at pH 3.5 and 9.0, respectively, and was stable at pH 9.0 (retained 75% activity after incubation at room temperature for 120 h). High enzyme affinity to ABTS is caused by an expanded area occupied by aromatic amino acid residues on its surface. Substrate-directed immobilization of the enzyme was performed using naphthylated multiwalled carbon nanotubes (MWCNTs), and a high oxygen reduction reaction potential (+0.62 V vs. normal hydrogen electrode (NHE)) was observed. The above-mentioned features make this enzyme a promising one for further studies in bioremediation and biological fuel cell technologies.

In this work, the electrochemical behaviour of bioelectrodes based on bacterial laccase Streptomyces carpinensis VKM Ac-1300 obtained using different immobilization methods was investigated. The bioelectrodes were formed by fixing the enzyme on the electrode surface by simple adsorption, by adsorption on the modified electrode by multi-walled carbon nanotubes and by covalent bounding of the enzyme by carboxyl groups with functionalized multi-walled carbon nanotubes. The orientation of immobilized laccase enzymes and their ability to direct and mediated electron transfer were assessed by direct amperometry at constant potential. It was found that, depending on the method of immobilization, from 5 to 10% of immobilized enzyme has the correct orientation and, consequently, the ability to direct electron transfer. At the same time, covalent bounding of protein on the surface of graphite electrodes modified with nanotubes leads to a more active direct electron transfer, an increase in the rate of oxygen reduction and long-term electrode stability. Thus, for bacterial laccase Streptomyces carpinensis VKM Ac-1300 the possibility of direct electron transfer at their immobilization by covalent bounding with carboxyl groups of multi-walled carbon nanotubes was shown. The developed bioelectrodes can be used as cathodes in biofuel cells.