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Item type:Publication, Access status: with files , Identification of genetic determinants that promote biofilm growth under heterotrophic conditions in Cupriavidus necator using transposon enrichment(Elsevier, 2026-09-01); ; ; Cupriavidus necator is a metabolically versatile β-proteobacterium of growing interest for auto- and heterotrophic bioprocesses, yet the genetic determinants governing its biofilm formation remain largely uncharacterized, particularly under process-relevant heterotrophic conditions. Here, we applied a forward-genetics transposon-enrichment approach to identify loci which promote surface-associated growth. A high-density mini-Tn5 mutant library (26,185 insertion clones, exceeding the >17,000 required for genome-wide coverage) was cultivated as a biofilm in a microfluidic flow-cell system on fructose for 168 h, and the surface-associated community was characterized by deep sequencing. Twelve genes showed significantly elevated insertion frequencies, several with documented links to biofilm formation in other bacteria, including the ferrous-iron uptake system (feoA/feoB), galU, and a GSDEF/EAL dual-domain protein. The gene B2043 (E6A55_RS29530), encoding this c-di-GMP-metabolizing protein, was selected for validation by markerless deletion. Under static conditions, the ΔB2043 mutant showed a 1.69 ± 0.06-fold increase in biofilm-associated biomass (p = 5.16 × 10<sup>−15</sup>). Under flow-through conditions, the mutant attached faster, entered exponential growth ∼10 h earlier, reached its biovolume plateau ∼16 h earlier than the wild-type, and formed distinct tower-like structures. These results identify B2043 as a negative regulator of biofilm formation acting predominantly during attachment, provide the first experimental evidence for c-di-GMP-dependent biofilm regulation in C. necator H16, and establish a functional-genomics framework — together with eleven further candidate loci — for engineering productive biofilms in this organism.Publicationtype: Journal Article16 10 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Aerographite vs Graphite: Investigating the role of electrode architecture in H2-mediated electroautotrophic biofilms(American Chemical Society (ACS), 2026-08-07); ; ; ; Oxic microbial electrosynthesis using aerobic hydrogenotrophic bacteria requires productive cathodic biofilm formation, yet reactive oxygen species (ROS) generated at the electrode surface present a critical barrier to initial colonization. This study investigates biofilm development by Cupriavidus necator H16 on Aerographite, an ultralow-density carbon foam (3–12 mg cm–3, porosity > 99%) with a hierarchical tetrapodal pore network, as a cathode material in microfluidic bioelectrochemical systems and compares it to graphite (a composite material consisting of graphite and polypropylene (PPG86)). A biphasic cultivation strategy, in which heterotrophic biofilm establishment preceded a switch to electroautotrophic conditions at −45.45 μA cm–2, successfully overcame the ROS barrier on both electrode materials. Noninvasive optical coherence tomography revealed a final biovolume of 0.086 mm3 mm–2 on graphite after 14 days, representing the first continuous kinetic characterization of C. necator cathode biofilm formation under defined flow conditions. Despite lower absolute biovolume per projected area, Aerographite supported higher biomass per unit electrode mass, reflecting its 585-fold higher mass-specific electroactive surface area relative to graphite. Scanning electron microscopy confirmed C. necator colonization of internal pore regions up to 500 μm below the electrode surface under laminar flow-over conditions. The macropore dimensions substantially exceed documented self-limiting biofilm thicknesses, indicating that pore occlusion is unlikely even at full biofilm development, and positioning Aerographite as a structurally enabling electrode material for smart, scalable, flow-through CO2 valorization systems.Publicationtype: Journal Article70 25 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Impact of permeability of triply periodic minimal surface-based substrates on multiwalled carbon nanotube growth(American Chemical Society (ACS), 2026-08-05); ; ; ; Lumpp, DominiqueDue to their excellent thermal and electrical properties combined with pronounced porosity, carbon nanotube forests are promising as catalyst support materials for smart reactors. To maximize catalytic turnover, it is essential to increase the available surface while maintaining precise control over reactant flow and heat distribution. In this work, multiwalled carbon nanotubes are grown on three-dimensional substrates based on triply periodic minimal surfaces, which offer superior mechanical properties alongside controlled flow dynamics and enhanced heat transfer rates. The substrates are fabricated via laser powder bed fusion and subsequently coated using injection chemical vapor deposition. To evaluate the design limitations of the three-dimensional substrates for CNT growth, the impact of a decreasing permeability on the coating’s morphology is investigated. As the permeability decreases with the unit cell size of the triply periodic minimal surfaces and the introduction of an external wall, the characteristic CNT forest structure gradually transforms. Provided that permeability and precursor accessibility to the internal surfaces remain sufficiently high, the morphology and composition of CNT forests closely resemble those grown on flat substrates. Introducing the wall leads to a transition from vertically aligned CNT forests to horizontally oriented CNT networks due to enhanced laminar-like flow characteristics. While less dense, it offers an increased CNT quality. Below a critical minimal permeability, carbon nanostructures with numerous defects form. The successful coating and control of its morphology enable the utilization of the CNT for further smart tailoring of the reactor.Publicationtype: Journal Article88 28 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Investigations on the role of support and synthesis procedure for the Rux–Cuy/CNT‐catalysed hydrogenolysis of glycerol to 1,2‐propanediol(Wiley, 2026-07-14); ; ; Tailoring support effects plays an important role for controlling activity and selectivity in heterogeneously catalyzed gas–liquid reactions. Sophisticated carbon supports like single‐ and multiwall carbon nanotubes (CNTs) as well as in house produced Globugraphite were used for the synthesis of bimetallic Ru–Cu catalysts, which were tested in a multibatch reactor setup for the chemical hydrogenolysis of glycerol to 1,2‐propanediol (1,2‐PDO) in aqueous solution. In‐depth characterization using multiple tools like inductively coupled plasma optical emission spectrometry, CHNS‐O analysis, N₂‐physisorption, scanning electron microscopy, transmission electron microscopy, energy‐dispersive X‐ray spectroscopy, powder X‐ray diffraction, H₂‐temperature programmed reduction, laser diffraction, and point of zero charge measurements revealed the dominating effects that the various carbon supports exert on the catalytic performance. The best‐performing catalyst synthesized by wetness impregnation consisted of Ru–Cu₃ nanoparticles (NPs) from mixed RuCl₃ and Cu(NO₃)₂ precursors dispersed on multiwall CNT Baytubes with a productivity of p = 12.74 g₁,₂‐PDO gactive metal ⁻¹ h⁻¹ . Its superior activity combined with high 1,2‐PDO selectivity (S= 75%) can be explained both by the nature of the highly dispersed Ru and Cu NPs showing the lowest reduction peak temperature on entangled tubes of CNT agglomerates demonstrating a high mesopore volume for optimal reactant accessibility and the highest specific surface area of all investigated materials. This lays the foundation for implementing this highly active and selective catalyst in a future SMART reactor for glycerol valorisation.Publicationtype: Journal Article57 40 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Enhancing swelling kinetics of pNIPAM lyogels: the role of crosslinking, copolymerization, and solvent(Elsevier, 2025-10-01); ; ; ; Stimuli-responsive lyogels are known for their ability to undergo significant macroscopic changes when exposed to external stimuli. While thermo-responsive gels, such as poly-N-isopropylacrylamide (pNIPAM), have been extensively studied across various applications, solvent-induced swelling has predominantly been investigated in aqueous solutions. This study explores the tailoring of lyogel formulations for future applications by controlling their solvent-induced swelling behavior, comparing both homopolymeric and semi-interpenetrating polymer networks (semi-IPNs). It is structured in two parts: the first focuses on characterization techniques, including NMR relaxometry, swelling degree measurements, mechanical testing, and SEM analysis, while the second part delves into swelling kinetic analysis, applying solvent exchange as a stimulus for varying gel formulations and solvents. In contrast to most previous studies, the impact of chemical and physical crosslinking, as well as copolymer inclusion, on the swelling behavior and mechanical properties of lyogels in organic solvents is examined and compared with solvent-induced swelling kinetics measurements. The results demonstrate that increasing chemically crosslinking in homopolymers and physically crosslinking in semi-IPNs enhances mechanical stability, while improving mass transport properties and solvent exchange kinetics. However, increases degree of crosslinking results in a prolonged response time to the solvent exchange stimulus and a reduction in the overall swelling capacity of the lyogels. Furthermore, variations in solvent properties, including molecular size and diffusion rates, significantly influence the swelling kinetics, whereas smaller, faster-diffusing solvents leading to more pronounced solvent spillage effects. Our findings highlight the complex interplay between gel formulation, network structure, and solvent nature in determining the solvent-induced swelling kinetics of lyogels, providing insights into how these materials can be tailored for specific applications especially those requiring short response times and optimized mechanical properties.Publicationtype: Journal Article110 61 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , 36 62