Protein-based foams are potential sustainable alternatives to petroleum-based polymer foams in e.g. single-use products. In this work, the biodegradation, bioassimilation, and recycling properties of glycerol-plasticized wheat gluten foams (using a foaming agent and gallic acid, citric acid, or genipin) were determined. The degradation was investigated at different pH levels in soil and high humidity. The fastest degradation occurred in an aqueous alkaline condition with complete degradation within 5 weeks. The foams exhibited excellent bioassimilation, comparable to or better than industrial fertilizers, particularly in promoting coriander plant growth. The additives provided specific effects: gallic acid offered antifungal properties, citric acid provided the fastest degradation at high pH, and genipin contributed with cross-linking. All three additives also contributed to antioxidant properties. Dense beta-sheet protein structures degraded more slowly than disordered/alpha-helix structures. WG foams showed only a small global warming potential and lower fossil carbon emissions than synthetic foams on a mass basis, as illustrated with a nitrile-butadiene rubber (NBR) foam. Unlike NBR, the protein foams could be recycled into films, offering an alternative to immediate composting.

Enzyme engineering is a powerful approach to enhancing biocatalytic performance and optimizing protein-based materials for diverse applications. This study employs ancestral sequence reconstruction (ASR), rational design, and process condition optimization to improve enzyme stability, catalytic efficiency, and functional properties. Four key areas are explored: transaminase engineering for chiral amine synthesis, enzymatic amide bond formation, Baeyer-Villiger oxidation selectivity control, and protein-based water-absorbing materials. To enhance the thermostability and substrate scope of ω-transaminase from Silicibacter pomeroyi(Sp-ATA), ASR was used to identify stabilizing mutations, improving its industrial suitability. For amide bond formation, rational design optimized Pseudomonas aeruginosa N-acyltransferase (PaAT), coupled with the adenylation domain of Segniliparus rugosus carboxylic acid reductase (CARsr-A). The engineered Y72S/F206N variant significantly enhanced conversion rates for pharmaceutically relevant carboxylic acids, providing a sustainable alternative to chemical synthesis. In Baeyer-Villiger oxidation, process optimization was investigated to control regioselectivity. Engineered Baeyer-Villiger monooxygenases (BVMOs) from Acinetobacter and Arthrobacter species shifted product distribution toward the"normal" lactone by increasing oxygen availability. For protein-based waterabsorbing materials, patatin mutagenesis altered charged amino acid composition. As demonstrated by molecular dynamics simulations, variants enriched in Lys and Asp doubled water absorption, demonstrating the potential of enzyme engineering in sustainable absorbent material development. This study integrates computational and experimental enzyme engineering strategies to improve biocatalysis for chemical synthesis and functional biomaterials, offering novel solutions for industrial biotechnology and sustainable material science.

Enzymingenjörskonst är en kraftfull strategi för att förbättra biokatalytisk prestanda och optimera proteinbaserade material för olika tillämpningar. Denna studie tillämpar rekonstitution av förfäderssekvenser (ASR), rationell design och optimering av processförhållanden för att förbättra enzymstabilitet, katalytisk effektivitet och funktionella egenskaper. Fyra centrala områden undersöks: transaminasdesign för syntes av kirala aminer, enzymatisk amidbildning, selektivitetskontroll vid Baeyer-Villiger-oxidation samt proteinbaserade vattenabsorberande material. För att förbättra termostabiliteten och substratspektra för ω-transaminaser från Silicibacter pomeroyi (Sp-ATA) användes ASR för att identifiera stabiliserande mutationer, vilket ökade enzymets industriella användbarhet. Vid amidbindningsbildning optimerades Pseudomonas aeruginosa N-acyltransferas (PaAT) genom rationell design och kombinerades med adenyleringsdomänen från Segniliparus rugosus karboxylsyrareduktas (CARsr-A). Den modifierade varianten Y72S/F206N visade en avsevärt förbättrad omvandlingshastighet för farmaceutiskt relevanta karboxylsyror, vilket erbjuder ett hållbart alternativ till kemisk syntes. I Baeyer-Villiger-oxidation undersöktes processoptimering för att styra regioselektiviteten. Ingenjörsmässigt modifierade Baeyer-Villiger monooxygenaser (BVMOs) från Acinetobacter- och Arthrobacter-arter kunde genom ökad syrgastillgänglighet styra produktfördelningen mot den "normala" laktonen. För proteinbaserade vattenabsorberande material genomfördes mutagenes på patatin, ett protein från potatis, för att förändra sammansättningen av laddade aminosyrarester. Varianter med en högre andel lysin och asparaginsyra uppvisade en fördubblad vattenabsorption, enligt molekylär dynamik-simuleringar, vilket demonstrerar potentialen hos enzymingenjörskonst för utveckling av hållbara absorberande material. Sammanfattningsvis belyser denna studieintegrationen av beräkningsbaserade och experimentella enzymteknikstrategier för att förbättra biokatalys vid kemisk syntes och för funktionella biomaterial, och erbjuder nya lösningar för industriell bioteknik och hållbar materialvetenskap.

Amine transaminases (ATAs), belonging to the class III transaminases within the superfamily of pyridoxal-5 '-phosphate-dependent enzymes, catalyze transamination reactions between amino donors and amino acceptors. These enzymes are particularly appealing for their role in stereospecific synthesis of chiral amines. However, the stability of most ATAs is not satisfying, limiting their suitability for industrial applications. Among them, the amine transaminase from Silicibacter pomeroyi (Sp-ATA) has drawn attention due to its high activity and broad substrate scope under mild conditions and high pH. Nevertheless, maintaining the activity at higher temperatures is a challenge. Previous studies to enhance enzyme function through directed evolution have shown promising results, yet predicting the cooperative effects of individual stabilizing mutations remains challenging. An alternative strategy is ancestral sequence reconstruction (ASR), which is based on gene sequences to create a more or less artificial phylogenetic tree. This study aims to leverage ASR techniques to explore the thermostability, solvent tolerance, and substrate profile of Sp-ATA, to find more stable transaminases. By using Sp-ATA as a template and incorporating insights from ancestral sequences, this strategy offers a promising approach for developing robust biocatalysts suitable for industrial applications.

Protein-based absorbent materials exhibit significant limitations in water retention compared to synthetic superabsorbent polymers (SAPs), widely used in agriculture, hygiene, and biomedical applications. Recent investigations have focused on leveraging highly soluble charged proteins such as patatin (a glycoprotein derived from potatoes) as natural alternatives to synthetic SAPs, given their unique structural properties and the opportunity they provide as sustainable raw material alternatives. This study investigates how the intrinsic amino acid composition and charged residues of patatin can be modified through mutagenesis to tailor its superabsorbent properties. Here, patatin was expressed in Escherichia coli to improve the water absorption capacity by altering its amino acid composition. By increasing liquid accessibility and charge density, our method of altering the charged profile of the protein significantly enhances the protein's swelling capacity, doubling its absorption compared to native patatin. Additionally, molecular dynamics simulations reveal that protein variants enriched with lysine and aspartic acid facilitate increased hydrogen bonding interactions with water molecules, thereby enhancing hydration. These results provide a fundamental understanding of how to tailor the physicochemical nature of proteins to develop them as viable bio-based absorbents for advanced sanitary applications, combining material science and biotechnology.

The drawbacks of amorphous hard carbon are its low conductivity and structural instability, due to its large volume change and the occurrence of side reactions with the electrolyte during cycling. Here, we propose a simple and rapid method to address these disadvantages; we used an emulsion solvent-evaporation method to create hierarchically structured microparticles of hard carbon nanoparticles, derived from soot, and multi-walled-carbon-nanotubes at a very low threshold of 2.8 wt%. These shrub-ball like microparticles have well-defined void spaces between different nanostructures of carbon, leading to an increased surface area, lower charge-resistance and side reactions, and higher electronic conductivity for Na+ insertion and de-insertion. They can be slurry cast to assemble Na+ anodes, exhibiting an initial discharge capacity of 713.3 mA h g(-1) and showing long-term stability with 120.8 mA h g(-1) at 500 mA g(-1) after 500 cycles, thus outperforming neat hard carbon nanoparticles by an order of magnitude. Our work shows that hierarchical self-assembly is attractive for increasing the performance of microparticles used for battery production.

Nanoplastics and microplastics (NMPs) in natural environments are an emerging global concern and understanding their formation processes from macro-plastic items during degradation/weathering is critical for predicting their quantities and impacts in different ecological systems. Here, we show the risk of enormous emissions of NMPs from polymer blends, a source that has not been specifically studied, by taking immiscible (most common case) partially biodegradable polymer blends as an example. The blends have the common “sea-island” morphology, where the minor non-biodegradable polymer phase (polyethylene and polypropylene) is dispersed as NMP particles in the major continuous biodegradable matrix (poly(ϵ-caprolactone)). The dispersed NMP particles with spherical and rod-like shapes are gradually liberated and released to the surrounding aquatic environment during the biodegradation of the matrix polymer. Strikingly, the number of released NMPs from the blend is very high. The blend film surface erosion process, induced by enzymatic hydrolysis of the matrix, involving fragmentation, hole formation, and hole wall detachment, was systematically investigated to reveal the NMP release process. Our findings present direct evidence and detailed insights into the high risk of emissions of NMPs from partially biodegradable immiscible polymer blends with a widespread “sea-island” morphology. Efforts from authorities, developers, manufacturers, and the public are needed to avoid the use of non-biodegradable polymers in blends with biodegradable polymers.