Bio-integrated carbon capture and utilization: at the interface between capture chemistry and archaeal CO reduction.

Carbon capture and utilization (CCU) covers an array of technologies for valorizing carbon dioxide (CO). To date, most mature CCU technology conducted with capture agents operates against the CO gradient to desorb CO from capture agents, exhibiting high energy penalties and thermal degradation due to the requirement for thermal swings. This Perspective presents a concept of Bio-Integrated Carbon Capture and Utilization (BICCU), which utilizes methanogens for integrated release and conversion of CO captured with capture agents.

Continuous biomethanation of flue gas-carbon dioxide using bio-integrated carbon capture and utilization.

Biomethanation of carbon dioxide (CO) from flue gas is a potential enabler of the green transition, particularly when integrated with the power-to-gas chain. However, challenges arise in achieving synthetic natural gas quality when utilizing CO from diluted carbon sources, and the high costs of CO separation using amine-based solutions make large-scale implementation unfeasible. We propose an innovative continuous biomethanation system that integrates carbon capture and CO stripping through microbial utilization, eliminating expenses with the stripper.

Electrical current disrupts the electron transfer in defined consortia.

Improving methane production through electrical current application to anaerobic digesters has garnered interest in optimizing such microbial electrochemical technologies, with claims suggesting direct interspecies electron transfer (DIET) at the cathode enhances methane yield. However, previous studies with mixed microbial communities only reported interspecies interactions based on species co-occurrence at the cathode, lacking insight into how a poised cathode influences well-defined DIET-based partnerships. To address this, we investigated the impact of continuous and discontinuous exposure to a poised cathode (-0.

Comparison of the photocatalytic degradability of PFOA, PFOS and GenX using Fe-zeolite in water.

Knowledge on the photocatalytic degradability of the emerging poly- and perfluorinated alkyl substances (PFAS) in water, specifically GenX, is limited. GenX has been detected globally in river water and is considered potentially more toxic than legacy PFAS. In this study, we compared the photocatalytic degradability of GenX with the legacy compounds perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) using Fe-zeolite photocatalysts.

Enhanced process control of trickle-bed reactors for biomethanation by vertical profiling directed by hydrogen microsensor monitoring.

Biomethanation is an emerging Power-to-X technology enabling CO valorisation to produce biomethane using renewable H. A promising reactor for facilitating biomethanation is the trickle bed reactor (TBR), however, these bioreactors are conventionally operated with a black-box approach, where the system is solely described by the input and output characteristics. This study employed a novel approach for process surveillance of internal dynamics in TBRs by installing multiple H microsensors along its vertical axis.

Complete defluorination of perfluorooctanoic acid (PFOA) by ultrasonic pyrolysis towards zero fluoro-pollution.

Advanced oxidation/reduction of PFAS is challenged and concerned by the formation of toxic, short-chain intermediates during water treatments. In this study, we investigated the complete defluorination of PFOA by ultrasound/persulfate (US/PS) with harmless end-products of CO, HO, and F ions. We observed 100% defluorination after 4 h of US treatment alone with a power input of 900 W.

Concentrate and degrade PFOA with a photo-regenerable composite of In-doped TNTs@AC.

"Concentrate-and-degrade" is an effective strategy to promote mass transfer and degradation of pollutants in photocatalytic systems, yet suitable and cost-effective photocatalysts are required to practice the new concept. In this study, we doped a post-transition metal of Indium (In) on a novel composite adsorptive photocatalyst, activated carbon-supported titanate nanotubes (TNTs@AC), to effectively degrade perfluorooctanoic acid (PFOA). In/TNTs@AC exhibited both excellent PFOA adsorption (>99% in 30 min) and photodegradation (>99% in 4 h) under optimal conditions (25 °C, pH 7, 1 atm, 1 g/L catalyst, 0.

Hydrodynamic analysis of full-scale in-situ biogas upgrading in manure digesters.

The addition of hydrogen to anaerobic digesters is an emerging technique for the sustainable upgrading of biogas to biomethane with renewable electricity. However, it is critically dependent on the effective gas-liquid transfer of hydrogen, which is a sparingly soluble gas. Very little is known about the impact of liquid and gas flow and bubble size on gas-liquid transfer during H injection in full-scale anaerobic digesters.

Cellulolytic and Xylanolytic Microbial Communities Associated With Lignocellulose-Rich Wheat Straw Degradation in Anaerobic Digestion.

The enzymatic hydrolysis of lignocellulosic polymers is generally considered the rate-limiting step to methane production in anaerobic digestion of lignocellulosic biomass. The present study aimed to investigate how the hydrolytic microbial communities of three different types of anaerobic digesters adapted to lignocellulose-rich wheat straw in continuous stirred tank reactors operated for 134 days. Cellulase and xylanase activities were monitored weekly using fluorescently-labeled model substrates and the enzymatic profiles were correlated with changes in microbial community compositions based on 16S rRNA gene amplicon sequencing to identify key species involved in lignocellulose degradation.

Stick or leave - Pushing methanogens to biofilm formation for ex situ biomethanation.

Biomethanation exploits the ability of methanogenic archaea to convert CO and renewable H from electrolysis to biomethane. Biofilm reactors are promising for biomethanation scale-up due to high CH productivity and low energy input for H gas-liquid mass transfer. Effects of operational conditions on biofilm dynamics remain largely uncharacterized but may increase reactor potentials further.

Anammox and partial nitritation in the mainstream of a wastewater treatment plant in a temperate region (Denmark).

The Marselisborg WWTP (Aarhus, Denmark) fed the mainstream nitrification/denitrification tanks with excess sludge from a sidestream DEMON tank for more than three years to investigate if anammox can supplement conventional nitrification/denitrification in a mainstream of a temperate region. To evaluate this long-term attempt, anammox and also denitrification rates were measured in activated sludge from the main- and sidestream at 10, 20 and 30 °C using N-labelling (stable isotope) experiments. The results show that anammox contributes by approximately 1% of the total nitrogen removal in the mainstream tanks and that anammox conversion rates there are approximately 800-900 times lower than in the DEMON.

Biogas upgrading with hydrogenotrophic methanogenic biofilms.

Hydrogen produced from periodic excess of electrical energy may be added to biogas reactors where it is converted to CH that can be utilized in the existing energy grid. The major challenge with this technology is gas-to-liquid mass transfer limitation. The microbial conversions in reactors designed for hydrogenotrophic methanogenesis were studied with microsensors for H, pH, and CO.

How Low Can You Go: Methane Production of at Low CO Concentrations.

Autotrophic hydrogenotrophic methanogens use H/CO as sole carbon and energy source. In contrast to H, CO is present in high concentrations in environments dominated by methanogens e.g.

An overview of microbial biogas enrichment.

Biogas upgrading technologies have received widespread attention recently and are researched extensively. Microbial biogas upgrading (biomethanation) relies on the microbial performance in enriched H and CO environments. In this review, recent developments and applications of CH enrichment in microbial methanation processes are systematically reviewed.

Parameters affecting acetate concentrations during in-situ biological hydrogen methanation.

Surplus electricity may be supplied to anaerobic digesters as H gas to upgrade the CH content of biogas. Acetate accumulation has been observed following H injections, but the parameters determining the degree of acetate accumulation are not well understood. The pathways involved during H consumption and acetate kinetics were evaluated in continuous lab reactors and parallel batch C experiments.

Primary sewage sludge filtration using biomass filter aids and subsequent hydrothermal co-liquefaction.

Hydrothermal liquefaction (HTL) is a promising technology for biofuel production and treatment of wastewater sludge. The current study investigates a novel utilization of biomass-assisted filtration of primary sludge to obtain high dry matter (DM) content sludge. Drastic improvements in filtration speed are achieved using different types of lignocellulosic biomass filter aids prepared via mechanical pre-treatment.

Influence on anaerobic digestion by intermediate thermal hydrolysis of waste activated sludge and co-digested wheat straw.

This paper analyses time (30 and 60 min) and temperature (120-190 °C) effects of intermediate thermal hydrolysis (ITHP) in a two-step anaerobic digestion of waste activated sludge (WAS) with and without wheat straw as a co-substrate. Effects were analyzed by measuring biochemical methane potential for 60 days and assessing associated kinetic and chemical data. Compared to non-treatment, ITHP increased the secondary step methane yield from 52 to 222 L CH kg VS and from 147 to 224 L CH kg VS for pre-digested WAS and pre-co-digested WAS respectively at an optimum of 170 °C and 30 min.

Small temperature differences can improve the performance of mesophilic sludge-based digesters.

Objective: To assess the effect of small temperature increases in mesophilic sludge-based digesters in order to develop and evaluate strategies for improving the biogas production in full-scale digesters.

Results: Methane production was strongly affected by small temperature differences, and this result was consistent across samples from 15 full-scale digesters. The specific methane yield varied between 42 and 97.

Removal of antibiotics during the anaerobic digestion of pig manure.

Antibiotics are frequently used in animals to treat sickness and prevent infection especially in industrial meat production. Some of the antibiotics cannot be completely metabolized and, as an unavoidable result, are excreted and thus end up in manure which is then spread in the environment. Currently increasing amounts of manure is used in biogas production before spreading the residuals on agricultural fields.

In-situ biogas upgrading with pulse H additions: The relevance of methanogen adaption and inorganic carbon level.

Surplus electricity from fluctuating renewable power sources may be converted to CH via biomethanisation in anaerobic digesters. The reactor performance and response of methanogen population of mixed-culture reactors was assessed during pulsed H injections. Initial H uptake rates increased immediately and linearly during consecutive pulse H injections for all tested injection rates (0.

Micro-scale H2-CO2 Dynamics in a Hydrogenotrophic Methanogenic Membrane Reactor.

Biogas production is a key factor in a sustainable energy supply. It is possible to get biogas with very high methane content if the biogas reactors are supplied with exogenous hydrogen, and one of the technologies for supplying hydrogen is through gas permeable membranes. In this study the activity and stratification of hydrogen consumption above such a membrane was investigated by use of microsensors for hydrogen and pH.

Anaerobic digestion of sulfate-acidified cattle slurry: One-stage vs. two-stage.

Two strategies to include acidified cattle manure (AcCM) in co-digestion with normal cattle manure (CM) are presented in this work. The strategies are a single thermophilic (50 °C) continuous stirred tank reactor (CSTR) anaerobic digestion and a two-step (65 °C + 50 °C) CSTR process. In both strategies, two different inclusion levels of H2SO4-acidified CM (10% and 20%) in co-digestion with normal CM were tested and compared with a control CSTR fed only CM.

Distribution and rate of microbial processes in an ammonia-loaded air filter biofilm.

The in situ activity and distribution of heterotrophic and nitrifying bacteria and their potential interactions were investigated in a full-scale, two-section, trickling filter designed for biological degradation of volatile organics and NH(3) in ventilation air from pig farms. The filter biofilm was investigated by microsensor analysis, fluorescence in situ hybridization, quantitative PCR, and batch incubation activity measurements. In situ aerobic activity showed a significant decrease through the filter, while the distribution of ammonia-oxidizing bacteria (AOB) was highly skewed toward the filter outlet.

Patient attitudes towards twin pregnancies and single embryo transfer - a questionnaire study.

Background: The present trend towards selective single embryo transfer (SET) calls for evaluation of patient attitudes towards twins and how the patients balance advantages and disadvantages of one or two embryos in IVF/ICSI treatment.

Methods: The study was conducted in a Danish public fertility clinic, where the common practice was double embryo transfer (DET), and the number of reimbursed treatments was limited to three. Referred patients were given oral and written information about the IVF/ICSI treatment including twin probability following DET and the risk of preterm delivery and neonatal complications associated with twins.

Murine pre-embryo oxygen consumption and developmental competence.

Purpose: In search for a new marker of preimplantation embryo viability the present study investigated oxygen consumption of individual cleavage stage murine embryos, and evaluated the predictive value regarding subsequent development to expanded blastocysts.

Methods: In all, 248 embryos were investigated from 2 cell stage until blastocyst stage with individual measurement of oxygen consumption and recording of developmental stage. Cleavage stage embryos and morula were divided in groups according to their oxygen consumption, and odds ratios (OR) for subsequent development to expanded blastocyst were calculated.