Carbon Compounds Research Articles

Bulk Layering Effects of Ag and Cu for Tandem CO2 Electrolysis.

The electrochemical reduction of carbon dioxide (CO2) presents an opportunity to close the carbon cycle and obtain sustainably sourced carbon compounds. In recent years, copper has received widespread attention as the only catalyst capable of meaningfully producing multi-carbon (C2+) species. Notably carbon monoxide (CO) can also be reduced to C2+ compounds on copper, motivating tandem systems that combine copper and CO-producing species, like silver, to enhance overall C2+ selectivities. In this work, we examine the impact of layered-combinations of bulk Cu and Ag by varying the location and proportion of the CO-producing Ag layer. We report an effective increase in the C2+ oxygenate selectivity from 23 % with a 100 nm Cu to 38 % for a 100 : 15 nm Cu : Ag layer. Notably, however, for all co-catalyst cases there is an overproduction of CO vs Cu alone, even for 5 nm Ag layers. Lastly, due to restructuring and interlayer mobility of the copper layer it is clear that the stability of copper limits the locational advantages of such tandem solutions.

Changes in Ibuprofen Toxicity and Degradation in Response to Immobilization of Bacillus thuringiensis B1(2015b)

Ibuprofen is one of the most commonly used anti-inflammatory drugs by humans, resulting in its appearance in the environment, which can negatively affect organisms living in it. The studies undertaken have shown that the immobilized Bacillus thuringiensis B1(2015b) strain can decompose this drug at a rate of qmax = 0.36 mg/L*h, with a Ks constant of 0.95 mg/L for this process. An analysis of the effect of ibuprofen on the metabolic profile of the immobilized strain B1(2015b) showed an increase in the consumption of carbon, nitrogen, phosphorus, and sulfur compounds by this strain compared to the free strain. Studies on the toxicity of ibuprofen against the B1(2015b) strain indicated a small protective effect of the carrier, manifested by a slightly higher EC50 value = 1190 mg/L (for the free strain EC50 = 1175 mg/L). A toxicity analysis of intermedia formed during ibuprofen degradation indicated that the increase in toxicity is positively correlated with the degree of hydroxylation of ibuprofen metabolites. A toxicity analysis of the post-culture fluid obtained after ibuprofen degradation by the immobilized and free strain indicated that the products formed due to this process are completely safe.

Microbial communities in slow sand filters for drinking water treatment adapt to organic matter altered by ozonation

Changing natural organic matter quality from anthropogenic activity and stricter requirements for micropollutant removal challenges existing systems for drinking water production. Ozonation of water followed by biofiltration, such as passage through a slow sand filter (SSF), is a partial solution. Biofiltration relies on biofilms (microbial communities within extracellular matrices). However, the effects of ozonation on SSF microbial communities are unknown. In this study, genome-resolved and read-based metagenomics were used to compare the microbial communities of two full-scale SSFs employing conventional pre-treatment to a 20 m2 SSF operated in parallel with ozonation as additional pre-treatment.The SSF microbial community receiving ozonated water was less diverse than those receiving non-ozonated water. Families Hyphomicrobiaceae, Acetobacteraceae, Sphingomonadaceae and Burkholderiaceae were more abundant when ozone was used, as were genes for metabolism of single-carbon organic compounds. Conversely, genes for metabolism of aromatic compounds and fatty acids were less abundant. Metagenome assembled genomes associated with the non-ozonated SSFs were enriched with several glycoside hydrolases, while those associated with the ozonated SSF were enriched with genes for 1-2 carbon compound metabolism. No indications of increased microbial risk (pathogens or antibiotic resistance genes) were detected as a consequence of ozonation.This study shows how microbial communities of SSFs adapt to changes in organic matter quality, highlighting the key role of biofilters for production of safe and sustainable drinking water in a changing climate.

Semiconducting biomass-based amorphous carbon films and their potential application in photovoltaic devices

Amorphous carbon (aC) is highly appealing because of its unique structure, electrical and optical properties, making it appropriate for various applications, especially in energy conversion. This work presents a comprehensive study on the synthesis of aC materials, including both intrinsic (i-type) and doped conditions (p- and n-type), to enhance the performance of photovoltaic films. Carbon materials are derived from biomass using a straightforward and environmentally conscious technique. The obtained carbon compound demonstrates an amorphous state with a substantial prevalence of the sp2 C=C component. Raman spectroscopy and electron microscopy confirmed the stacking of 2D layers forming a multilayer graphene structure. The carbon compound prepared AC films deposited onto a quartz glass surface via spray coating. The films have a thickness ranging from 247 to 478 nm. The dielectric constants of the optical parameters reveal resonant exciton features at a photon energy of ∼3.8 eV, whereas the real component exhibits semiconductive properties. The refractive indices of the p-, i-, and n-layers, which have gap energies in decreasing order, demonstrate a decline. The optical conductivity of aC is higher than that of amorphous silicon, specifically 0.54 × 103Ω−1cm−1, 0.48 × 103 Ω−1cm−1, and 0.53 × 103 Ω−1cm−1 for the p-, i-, and n-type films, respectively. Based on this outcome, it is reasonable to suggest that the recently developed material is potentially important as a photovoltaic device.

In vitro cell viability evaluation of amorphous carbon and Fe3O4 compounds

In vitro cell viability evaluation of amorphous carbon and Fe3O4 compounds

Electrochemical degradation of aromatic organophosphate esters: Mechanisms, toxicity changes, and ecological risk assessment

Aromatic organophosphate esters (AOPEs), including triphenyl phosphate (TPHP), tricresyl phosphate (TCP), and 2-ethylhexyl diphenyl phosphate (EHDPP), pose significant health and ecological risks. Electrochemical advanced oxidation process (EAOP) is effective in removing refractory pollutants. In this study, the degradation performance and detoxication ability of AOPEs by EAOP were investigated. Hydroxylation, oxidation, and bond cleavage products were identified as major degradation products (DPs) due to the reaction with ·OH and O₂·-. Toxicity assessments using ecological structure activity relationship (ECOSAR) model and flow cytometry (FCM) revealed the cytotoxicity and aquatic toxicity for DPs were significantly decreased. 16S rRNA gene sequencing of sediment exposure to AOPEs and DPs were applied to assess ecological toxicity, and results showed reduced bacterial richness and diversity with EHDPP and TCP, while TPHP slightly enhanced richness. AOPEs and DPs altered bacterial genera involved in carbon, nitrogen, sulfur cycling and organic compound degradation. Bacterial community assembly suggested elevated stochastic processes and reduced ecotoxicity, confirming AOPEs can be effectively detoxified by 10-min EAOP treatment. Molecular ecological network analysis indicated increased complexity and stability of bacterial communities with DPs. These findings comprehensively revealed the toxicity of AOPEs and their DPs and provided the first evidence of effective degradation and detoxification by EAOP from ecotoxicological perspective.

Theoretical and experimental analysis of the modulated phase grating X-ray interferometer.

X-ray grating interferometry allows for the simultaneous acquisition of attenuation, differential-phase contrast, and dark-field images, resulting from X-ray attenuation, refraction, and small-angle scattering, respectively. The modulated phase grating (MPG) interferometer is a recently developed grating interferometry system capable of generating a directly resolvable interference pattern using a relatively large period grating envelope function that is sampled at a pitch that is small enough that X-ray spatial coherence can be achieved by using a microfocus X-ray source or G0 grating. We present the theory of the MPG interferometry system for a 2-dimensional staggered grating, derived using Fourier optics, and we compare the theoretical predictions with experiments we have performed with a microfocus X-ray system at Pennington Biomedical Research Center, LSU. The theoretical and experimental fringe visibility is evaluated as a function of grating-to-detector distance. Additionally, quantitative experiments are performed with porous carbon and alumina compounds, and the mean normalized dark-field signal is compared with independent porosimetry measurements. Qualitative analysis of attenuation and dark-field images of a dried anchovy are shown.

The Effect of DLC Surface Coatings on Microabrasive Wear of Ti-22Nb-6Zr Obtained by Powder Metallurgy

Titanium alloys have a high cost of production and exhibit low resistance to abrasive wear. The objective of this work was to carry out diamond-like carbon (DLC) coating, with dissimilar thicknesses, on Ti-22Nb-6Zr titanium alloys produced by powder metallurgy, and to evaluate its microabrasive wear resistance. The samples were compacted, cold pressed, and sintered, producing substrates for coating. The DLC coatings were carried out by PECVD (plasma-enhanced chemical vapor deposition). Free sphere microabrasive wear tests were performed using alumina (Al2O3) abrasive suspension. The DLC-coated samples were characterized by scanning electron microscopy (SEM), Vickers microhardness, coatings adhesion tests, confocal laser microscopy, atomic force microscopy (AFM), and Raman spectroscopy. The coatings did not show peeling-off or delamination in adhesion tests. The PECVD deposition was effective, producing sp2 and sp3 mixed carbon compounds characteristic of diamond-like carbon. The coatings provided good structural quality, homogeneity in surface roughness, excellent coating-to-substrate adhesion, and good tribological performance in microabrasive wear tests. The low wear coefficients obtained in this work demonstrate the excellent potential of DLC coatings to improve the tribological behavior of biocompatible titanium alloy parts (Ti-22Nb-6Zr) produced with a low modulus of elasticity (closer to the bone) and with near net shape, given by powder metallurgy processing.

Optimization based process modeling of an anaerobic membrane bioreactor system: Application to swine wastewater

To maintain current levels of consumption in the economy with the dwindling supply of non-renewable material and energy, alternative resource streams more traditionally viewed as waste streams must be considered. Fermentation of high-strength wastewaters is one such pathway that allows for the recovery of energy, nitrogen, phosphorus, and carbon compounds. Anaerobic membrane bioreactors (AnMBRs) are an emerging technology that allow for the digestion of wastewater in a much smaller footprint than traditional anaerobic digesters. Adoption of this technology into industry has been limited by membrane capital and cleaning costs, but these costs may be offset through the recovery of valuable products. To evaluate the viability of AnMBR technology in the context of swine wastewater treatment, an optimization-based process model built upon Anaerobic Digestion Model No. 1 (ADM1) has been developed. Modeling results show that a swine wastewater stream provides potential for net positive energy generation from the AnMBR system in most cases. Sensitivity analyses around important variables were conducted to determine focus areas for future research into AnMBR technology and evaluate the robustness of the model to microbial variables that may change with different microbial communities.

Effect of sodium zeolite mixed metal oxide catalysts on catalytic conversion of mixed-density plastic into carbon nanotubes and hydrogen fuel

A combination of experimental and statistical analysis presents a comprehensive understanding of the microwave pyrolysis technique for catalytic deconstruction of mixed-density plastics. By optimizing the process parameters and catalyst selection, it is possible to maximize the production of valuable solid and energy products, contributing to sustainable waste management. In this work, different mixed-density plastics were pyrolyzed with different catalysts and residence times to yield liquid fuel, syngas, and structured carbon residue. The effect of inputs on the product type, yield and composition was statistically evaluated using ANOVA, which showed an F value of 4.108 and a p-value of 0.098 (>1.00). FTIR and GC-MS revealed that the oil product consisted of C13+ fractions in the form of alkanes, alkenes, and aromatics. The microscopic analysis of the residue confirmed the formation of carbon nanotubes along with other amorphous products. The presence of impurities in the solid product was further analyzed through XRD analysis. The pyrolytic liquid fuel revealed the presence of conjugated aromatic structure and carbonyl group in their concentration. This research demonstrated that converting mixed-density plastics using sodium zeolite, aluminum oxide, and nickel oxide catalysts yields 84% valuable products, confirming wasted plastics as a lucrative energy feedstock for producing hydrogen and high-value carbon compounds.

Nearly 30a shrub introduction in desert steppes has led to an increase in saprotrophic fungi, accelerating the degradation of carbon compounds and nitrate reduction

Clarifying how soil microbial communities respond to shrub introduction after overgrazing in desert steppe and their potential functions is crucial for understanding the biogeochemical processes involved in vegetation transformation and sustainability of desert grasslands. However, the dynamics of microbial communities remain poorly understood. We selected enclosed grasslands (20a), overgrazed grasslands, and shrublands (6a, 15a, and 25a) to explore how shrubs introduced influence soil microbial structure and functional groups over the long term after desert grassland degradation. The results showed that overgrazing and shrub introduction (Caragana korshinskii) had more significant impacts on microbial β diversity than on α diversity. Fungal communities were more sensitive to grassland degradation. In contrast, introducing shrubs affected both fungal and bacterial communities, and an increase in shrub age drove the synergistic effects of fungal species. Soil nitrate and microbial biomass nitrogen were the key factors affecting bacterial and fungal communities. Compared with enclosed grasslands, overgrazing and introducing shrubs significantly increased soil nitrate reduction, ectomycorrhizals, and endophytes. The introduction of shrubs after overgrazing in desert steppe further enhanced the decomposition of carbon compounds and reduced processes such as denitrification. During shrub introduction, total phosphorus, nitrate–nitrogen, and N-acetylglucosaminidase were key factors affecting carbon, nitrogen, and fungal functional groups. Variations in microbial diversity and functional groups, through their influence on extracellular enzymes activity and the availability of microbial biomass nutrients, ultimately explained 85%, 42%, and 34% the observed variations in soil carbon, nitrogen, and phosphorus content, respectively. This study aimed to investigate the long-term effects of anthropogenic shrub expansion on the structure and function of soil microbial communities in degraded desert steppes, provide a scientific basis for steppe restoration and management, and further understand their significance for ecosystem sustainability.

Sustainable waste-treating-waste strategy: Catalytic recycling of polyethylene terephthalate over reconstructed waste catalysts

Polyethylene terephthalate (PET) is the most widely used polyester plastic, but difficulties associated with PET recycling have led to significant environmental issues. The recycling of PET waste into building monomers and valuable chemicals has attracted increasing attention. Herein, we propose a sustainable circular strategy for efficiently hydrogenolytic depolymerizing the waste PET by using reconstructed spent catalysts from the heavy oil slurry-phase hydrocracking. Two types of molybdenum sulphide/activated petroleum-based carbon compounds, a-MoSx/APC and MoS2/APC, were constructed using waste refining catalyst through the activation and annealing methods, which were used as catalysts for the hydrogenolytic depolymerisation of waste PET. Experimental results revealed that the different active components in the two reconstructed catalysts, molybdenum sulphide clusters, and few-layered molybdenum disulfide, show different activity and selectivity for the catalytic depolymerisation of PET. After the β-scission process of PET, the formed intermediate vinyl-terminated carboxylate units are converted to monoethyl terephthalate (MET) through a CC insertion pathway catalyzed by MoV, while to terephthalic acid (TPA) through a hydrogenolysis pathway catalyzed by MoIV. Therefore, MoS2/APC converts PET to TPA with a yield of 83 % within 24 hours at 270 °C under 1 atmosphere of H2 and solvent-free conditions, without generating any MET products. Moreover, this process is effective for both commercial and waste PET, and the catalyst could be reused for at least ten runs with stable activity. The sustainable waste-treating-waste strategy highlights a potential approach to the circular economy.

A sustainable black liquor-based carbon scavenger to promote urea formaldehyde as green wood adhesive with low formaldehyde emission

The current study focuses on finding an ecological method to dispose of black liquors (BLs), containing lignin macromolecules, which are produced as byproducts of rice straw-based paper production. In addition to maximizing their value as precursors in the preparation of novel formaldehyde scavengers to avoid the environmental risks associated with using urea formaldehyde in agro-wood composites. To optimize the route, various black liquors are prepared from pulping of rice straw by different pulping agents (alkali, neutral, acidic and kraft reagents) used as additions or precursors for carbon compounds. Elemental analysis, thermogravimetric analysis [TGA], Fourier transform infrared [FTIR] and scanning electron microscope (SEM), are the techniques used to characterize the BLs; while the gel time, bond strength, and differential scanning calorimetry (DSC) methodologies are applied to determine the impact of black liquor (BL) and black liquor‑carbon nanostructures (BL-CNSs) on performance of urea formaldehyde (UF) adhesive. The behavior of the investigated BL-CNSs as HCHO-scavengers is assessed from their affinity to capture the HCHO, and reduction of free-HCHO in UF-palm fibers agro-composites. BL-CNSs, as novel scavengers, exhibit promising properties where the bonding strength of BL-CNSs-UF adhesives increased to 19.7 MPa even though the UF was only 8.4 MPa. Moreover, the formaldehyde adsorption capacity ranges from 35.4 to 63.6 mg/g as well as lowering the gel time. It is interesting to note that the investigated scavengers not only reduced the free-HCHO of composites by about 40–91 %, but also enhancement in their mechanical and water resistance properties; where the modulus of rupture (MOR), internal bond (IB) and reduction in thickness swelling improved to about 50 % and 83.3 %, and 38.8 %, respectively. According to the American National Standards Institute (ANSI) standard these new scavengers, especially from BL of neutral pulping, permit the production of an eco-board (E1) with static bending exceeding the H-3 class.

Photosynthetic Electron Flows and Networks of Metabolite Trafficking to Sustain Metabolism in Photosynthetic Systems.

Photosynthetic eukaryotes have metabolic pathways that occur in distinct subcellular compartments. However, because metabolites synthesized in one compartment, including fixed carbon compounds and reductant generated by photosynthetic electron flows, may be integral to processes in other compartments, the cells must efficiently move metabolites among the different compartments. This review examines the various photosynthetic electron flows used to generate ATP and fixed carbon and the trafficking of metabolites in the green alga Chlamydomomas reinhardtii; information on other algae and plants is provided to add depth and nuance to the discussion. We emphasized the trafficking of metabolites across the envelope membranes of the two energy powerhouse organelles of the cell, the chloroplast and mitochondrion, the nature and roles of the major mobile metabolites that move among these compartments, and the specific or presumed transporters involved in that trafficking. These transporters include sugar-phosphate (sugar-P)/inorganic phosphate (Pi) transporters and dicarboxylate transporters, although, in many cases, we know little about the substrate specificities of these transporters, how their activities are regulated/coordinated, compensatory responses among transporters when specific transporters are compromised, associations between transporters and other cellular proteins, and the possibilities for forming specific 'megacomplexes' involving interactions between enzymes of central metabolism with specific transport proteins. Finally, we discuss metabolite trafficking associated with specific biological processes that occur under various environmental conditions to help to maintain the cell's fitness. These processes include C4 metabolism in plants and the carbon concentrating mechanism, photorespiration, and fermentation metabolism in algae.

Modification and Functionalization of Separators for High Performance Lithium-Sulfur Batteries.

Lithium-sulfur batteries (LSB) have been recognized as a prominent potential next-generation energy storage system, owing to their substantial theoretical specific capacity (1675 mAh g-1) and high energy density (2600 Wh kg-1). In addition, sulfur's abundance, low cost, and environmental friendliness make commercializing LSB feasible. However, challenges such as poor cycling stability and reduced capacity, stemming from the formation and diffusion of lithium polysulfides (LiPSs), hinder LSB's practical application. Introducing functional separators represents an effective strategy to surmount these obstacles and enhance the electrochemical performance of LSBs. Here, we have conducted a comprehensive review of recent advancements in functional separators for LSBs about various (i) carbon and metal compound materials, (ii) polymer materials, and (iii) novel separators in recent years. The detailed preparation process, morphology and performance characterization, and advantages and disadvantages are summarized, aiming to fundamentally understand the mechanisms of improving battery performance. Additionally, the development potential and future prospects of advanced separators are also discussed.

Harnessing Biomass for a Sustainable Future: The Role of Starch and Lignin

The global climate crisis, driven by unchecked industrialization and ecological negligence, compels humanity to seek alternative ways to either avert or mitigate the disastrous environmental phenomena encountered, particularly in recent years. The significant quantities of biomass generated by human activities may serve as important resources for technological applications, and biomass valorization offers dual benefits. This review emphasizes the potential of starch and lignin as adaptable materials for the advancement of sustainable and eco-friendly technologies. By investigating catalytic alterations, we may advance a more sustainable future and tackle the escalating issues of environmental pollution and sustainability. Catalytic alterations of lignin and starch have become essential techniques for their valorization. Biopolymers can be changed into useful chemicals and materials, like levulinic acid, lactic acid, 5-HMF and modified starch, which are used in the paper, textile, and coatings industries. Besides transforming into chemicals, lignin and starch can produce reactive carbon compounds that find application in both classical chemistry and photocatalysis. Additionally, we can use their highly functionalized polymeric matrices as catalysts. We can change the polymeric matrices’ chemical backbone to make them better at speeding up reactions like cross-coupling and multicomponent reactions.

Undervalued role of metal-carbon junction in selective generation of H2O2: An example of the zinc-carbon junction edge providing asymmetric active sites for efficient oxygen reduction

The spontaneous oxygen reduction is a potential technology for in-situ H2O2 production, which gets rid of the dependence on electricity and solar energy. Previous some metal–carbon compounds reported are feasible to trigger oxygen reduction. These reports always claim the high H2O2 generation ability of metal–carbon composites, while rarely discuss the contribution of carbon and the carbon–metal junction to the oxygen reduction process. Inspired by the dual active sites, we infer that the role of interfacial carbon in metal–carbon composites is underestimated. By a heat treatment of the co-precipitate of zinc and glucose, the Zn-C junction is constructed in Zn-gc to achieve a spontaneous selective reduction of O2 to H2O2. The Zn-C interface edge is active site, where an asymmetric activation is achieved by bonding two O atoms from O2 to C and Zn, respectively. The Zn traction to one of the O atoms is mainly in xy plane, while the C traction to the other O atom is parallel to z-axis. The yield of H2O2 produced per gram of Zn increases from 27.89 mg to 122.21 mg, an improvement of 4.38 times. And the inertness of Zn and its oxygen-containing compounds towards H2O2 enables Zn-gc/O2 system to stabilize H2O2 over a long period of time. This work reveals the crucial role of neglected junction interfaces in oxygen reduction reactions in metal–carbon composites.

Metabolic mechanisms of carbon and nitrogen interactions during anaerobic digestion of coal

There was limited research on the impact of nitrogen metabolism in the process of methane production with coal, even if carbon and nitrogen metabolism were closely interconnected. Lignite was the source of carbon and nitrogen in anaerobic digestion system. The relationship between carbon and nitrogen metabolism was systematically discussed during the anaerobic digestion process. The results showed that phenolic carbon or ether carbon (C-O), pyridine-type nitrogen (N-6) and nitrogen oxide compound (N-X) in coal were decomposed under the action of Macellibacteroides, Sphaerochaeta and Trichococcus in the hydrolysis stage, respectively. In the acidogenesis stage, the stress of volatile fatty acids and ammonia produced by dissolved organic matter under the action of Syner-01 and Sphaerochaeta on hydrogenotrophic and acetoclastic methanogens was alleviated during the nitrogen cycle. In the acetogenesis stage, acetic acid produced from the decomposition of organic acids and alcohols by Synergistaceae and Sedimentibacter was competed by denitrifying bacteria and acetogenic methanogens. In the methanogenesis stage, CO2 was reduced by Methanobacterium and Methanoculleus to produce CH4, while acetic acid was decomposed by Methanosaeta to produce CH4. And methyl substances were generated into CH4 by Methanosarcina and Methanofastidiosum. This understanding will provide a basis for strengthening the favorable factors in biomethane production.

DBN-based molecular solvents for highly efficient and reversible CO2 capture

Reducing greenhouse gas emissions is a crucial step in mitigating global warming. Carbon dioxide (CO2) represents one of the most pivotal greenhouse gases contributing to climate change. Many researchers are actively engaged in the development of effective and reversible CO2 absorbents to control and reduce CO2 gas emissions. In this paper, we synthesized a series of molecular solvents (MSs) based on the superbase 1,5-diazabicyclo [4.3.0]-5-nonene (DBN) and used them for CO2 capture. The CO2 capture capacity of MSs composed of DBN and different alcohols was systematically investigated, with DBN-Methanol (1:1.25) demonstrating superior absorption performance by achieving a maximum absorption capacity of 0.263 g CO2/g MS. The effects of temperature, pressure, the molar ratio of the hydrogen bond acceptor (HBA) to hydrogen bond donor (HBD), and moisture on the absorption process were studied. The experimental results were corroborated by NMR spectra analysis and FTIR spectra analysis, confirming that these MSs can effectively react with CO2 to produce carbonate and carbamate compounds through synergistic absorption involving hydroxyl group as primary component and amino group as secondary component. In addition, it is worth noting that the MSs studied in this work exhibit only glass transition at low temperatures and transform into ionic liquids (ILs) after capturing CO2, resulting in a significant increase in conductivity and demonstrating considerable electrochemical potential.

Algae-fungi symbioses and bacteria-fungi co-exclusion drive tree species-specific differences in canopy bark microbiomes.

With over 3 trillion trees, forest ecosystems comprise nearly one-third of the terrestrial surface of the Earth. Very little attention has been given to the exploration of the above-ground plant microbiome of trees, its complex trophic interactions, and variations among tree species. To address this knowledge gap, we applied a primer-independent shotgun metatranscriptomic approach to assess the entire living canopy bark microbiome comprising prokaryotic and eukaryotic primary producers, decomposers, and various groups of consumers. With almost 1500 genera, we found a high microbial diversity on three tree species with distinct bark textures: oak (Quercus robur), linden (Tilia cordata), both with rough bark, and maple (Acer pseudoplatanus) with smooth bark. Core co-occurrence network analysis revealed a rich food web dominated by algal primary producers, and bacterial and fungal decomposers, sustaining a diverse community of consumers, including protists, microscopic metazoans and predatory bacteria. Whereas maple accommodated a depauperate microbiome, oak and linden accommodated a richer microbiome mainly differing in their relative community composition: Bacteria exhibited an increased dominance on linden, whereas co-occurring algae and fungi dominated on oak, highlighting the importance of algal-fungal lichen symbioses even at the microscopic scale. Further, due to bacteria-fungi co-exclusion, bacteria on bark are not the main beneficiaries of algae-derived carbon compounds as it is known from aquatic systems.