Enzymes are nature’s catalyst of choice for the highly selective and efficient coupling of carbohydrates. Enzymatic sugar coupling is a competitive technology for industrial glycosylation reactions, since chemical synthetic routes require extensive use of laborious protection group manipulations and often lack regio- and stereoselectivity. The application of Leloir glycosyltransferases has received considerable attention in recent years and offers excellent control over the reactivity and selectivity of glycosylation reactions with unprotected carbohydrates, paving the way for previously inaccessible synthetic routes. The development of nucleotide recycling cascades has allowed for the efficient production and reuse of nucleotide sugar donors in robust one-pot multi-enzyme glycosylation cascades. In this way, large glycans and glycoconjugates with complex stereochemistry can be constructed. With recent advances, LeLoir glycosyltransferases are close to being applied industrially in multi-enzyme, programmable cascade glycosylations.

Silica monoliths featuring either mesopores or flow-through macropores and mesopores in their skeleton are prepared by combining spinodal phase separation and sol-gel condensation. The macroporous network is first generated by phase separation in acidic medium in the presence of polyethyleneoxides while mesoporosity is engineered in a second step in alkaline medium, possibly in the presence of alkylammonium cations as surfactants. The mesoporous monoliths, also referred as aerogels, are obtained in the presence of alkylpolyethylene oxides in acidic medium without the use of supercritical drying. The impact of the experimental conditions on pore architecture of the monoliths regarding the shape, the ordering, the size and the connectivity of the mesopores is comprehensively discussed based on a critical appraisal of the different models used for textural analysis.

Enzymes are supreme catalysts when it comes to high enantiopurities and their immobilization will pave the way for continuous operation. In this context, we show the covalent immobilization of hydroxynitrile lyases HbHNL (from Hevea brasiliensis) and MeHNL (from Manihot esculenta) in a siliceous monolithic microreactor for continuous operation. A thorough characterization of the immobilized HNLs on mesoporous silicates indicated the conditions essential for a successful immobilization. Their application in a continuous flow system enabled a remarkably fast (3.2 min) production of chiral cyanohydrins with high conversion (97%) and high ee (98%) using minimal enzyme loading (STY = 71 g L⁻¹ h⁻¹ mg_protein ⁻¹). MeHNL showed increased operational stability, possibly due to a structural difference. The continuous flow microreactor outperformed batch systems, demonstrating the advantage of the mesoporous/macroporous environment for the expression of enzyme activity and the favorable characteristics of the microreactor. Overall, the system shows great potential for future industrial application of biocatalytic asymmetric syntheses.

Acyltransferase from Mycobacterium smegmatis (MsAcT) immobilised in continuous-flow microchannel (30–50 μm dia.) reactors with hierarchical pore structure (4 cm³ g⁻¹ total pore volume) enabled quantitative, full and rapid transesterification of neopentylglycol (NPG) with ethyl acetate in a biphasic 50/50% system in less than one minute. MsAcT was attached either covalently via amino groups or by a specific His-tag-mediated adsorption on Ni or Co sites. Both methods gave similar results for enzyme loading (ca. 3 mg g⁻¹ carrier, 60–70% immobilisation yield) and specific activity. The experiments revealed that the rate of monoester formation in the microreactor was exceedingly fast compared to that of diester synthesis and also the native enzyme behaviour in a batch reactor. The studies show that the course of transesterification was fully controlled by the biocatalytic properties of MsAcT confined in the mesoporous environment. These findings may be of significant interest from both fundamental and practical perspectives.

Various types of mesoporous silica were used as carriers to synthesize a series of immobilized imidazolium-based ionic liquids. Their activity was tested in the synthesis of styrene carbonate from CO₂ and styrene. This is one-pot process, whereby two stages are carried out in one reactor and there is no need to isolate the intermediate product, epoxide. A systematic study on the influence of parameters such as temperature, the reaction time, CO₂ pressure, as well as the amount and type of catalyst used was carried out. A strong synergistic catalytic effect of ionic liquid and Lewis acid was observed in promoting this reaction. The addition sequence of regents and amount of immobilized catalyst were considered crucial for the synthesis of styrene carbonate from CO₂ and styrene. The tested silica-supported ionic liquids gave an easily-recyclable system which under the most favorable conditions ([mtespim]Cl/@SiO₂; ZnBr₂, 0.1 mol%; 110 °C, 4 h, 1 MPa) can be reused without a significant loss of catalytic activity nor selectivity.