The complex structure of Fomes fomentarius represents an architectural design for high-performance ultralightweight materials.

High strength, hardness, and fracture toughness are mechanical properties that are not commonly associated with the fleshy body of a fungus. Here, we show with detailed structural, chemical, and mechanical characterization that Fomes fomentarius is an exception, and its architectural design is a source of inspiration for an emerging class of ultralightweight high-performance materials. Our findings reveal that F. fomentarius is a functionally graded material with three distinct layers that undergo multiscale hierarchical self-assembly. Mycelium is the primary component in all layers. However, in each layer, mycelium exhibits a very distinct microstructure with unique preferential orientation, aspect ratio, density, and branch length. We also show that an extracellular matrix acts as a reinforcing adhesive that differs in each layer in terms of quantity, polymeric content, and interconnectivity. These findings demonstrate how the synergistic interplay of the aforementioned features results in distinct mechanical properties for each layer.

Correction: ß-1,3-Glucan synthesis, novel supramolecular self-assembly, characterization and application.

Correction for 'ß-1,3-Glucan synthesis, novel supramolecular self-assembly, characterization and application' by Robert Pylkkänen et al., Nanoscale, 2022, https://doi.org/10.1039/D2NR02731C.

ß-1,3-Glucan synthesis, novel supramolecular self-assembly, characterization and application.

ß-1,3-Glucans are ubiquitously observed in various biological systems with diverse physio-ecological functions, yet their underlying assembly mechanism and multiscale complexation in vitro remains poorly understood. Here, we provide for the first-time evidence of unidentified ß-1,3-glucan supramolecular complexation into intricate hierarchical architectures over several length scales. We mediated these unique assemblies using a recombinantly produced ß-1,3-glucan phosphorylase (Ta1,3BGP) by fine-tuning solution conditions during particle nucleation and growth. We report a synthesis of interconnected parallel hexagonal lamellae composed of 8 nm thick sheets of highly expanded paracrystals. The architecture consists of ß-1,3-glucan triple-helices with considerable inter-intra hydrogen bonding within, as well as in between adjacent triple-helices. The results extend our understanding of ß-1,3-glucan molecular organization and shed light on different aspects of the crystallization processes of biomolecules into structures unseen by nature. The presented versatile synthesis yields new materials for diverse medical and industrial applications.

In Vitro Synthesis and Self-Assembly of Cellulose II Nanofibrils Catalyzed by the Reverse Reaction of Clostridium thermocellum Cellodextrin Phosphorylase.

In nature, various organisms produce cellulose as microfibrils, which are processed into their nano- and microfibrillar and/or crystalline components by humans in order to obtain desired material properties. Interestingly, the natural synthesis machinery can be circumvented by enzymatically synthesizing cellulose from precursor molecules in vitro. This approach is appealing for producing tailor-made cellulosic particles and materials because it enables optimization of the reaction conditions for cellulose synthesis in order to generate particles with a desired morphology in their pure form. Here, we present enzymatic cellulose synthesis catalyzed by the reverse reaction of Clostridium thermocellum cellodextrin phosphorylase in vitro. We were able to produce cellulose II nanofibril networks in all conditions tested, using varying concentrations of the glycosyl acceptors d-glucose or d-cellobiose (0.5, 5, and 50 mM). We show that shorter cellulose chains assemble into flat ribbon-like fibrils with greater diameter, while longer chains assemble into cylindrical fibrils with smaller diameter.

In vitro reconstitution and characterisation of the oxidative D-xylose pathway for production of organic acids and alcohols.

The oxidative D-xylose pathway, i.e. Dahms pathway, can be utilised to produce from cheap biomass raw material useful chemical intermediates. In vitro metabolic pathways offer a fast way to study the rate-limiting steps and find the most suitable enzymes for each reaction. We have constructed here in vitro multi-enzyme cascades leading from D-xylose or D-xylonolactone to ethylene glycol, glycolic acid and lactic acid, and use simple spectrophotometric assays for the read-out of the efficiency of these pathways. Based on our earlier results, we focussed particularly on the less studied xylonolactone ring opening (hydrolysis) reaction. The bacterial Caulobacter crescentus lactonase (Cc XylC), was shown to be a metal-dependent enzyme clearly improving the formation of D-xylonic acid at pH range from 6 to 8. The following dehydration reaction by the ILVD/EDD family D-xylonate dehydratase is a rate-limiting step in the pathway, and an effort was made to screen for novel enolase family D-xylonate dehydratases, however, no suitable replacing enzymes were found for this reaction. Concerning the oxidation of glycolaldehyde to glycolic acid, several enzyme candidates were also tested. Both Escherichia coli aldehyde dehydrogenase (Ec AldA) and Azospirillum brasilense α-ketoglutarate semialdehyde dehydrogenase (Ab AraE) proved to be suitable enzymes for this reaction.