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Abstract Antibiotics are extensively used in human medicine, aquaculture, and animal husbandry, leading to the release of antimicrobial resistance into the environment. This contributes to the rapid spread of antibiotic-resistant genes (ARGs), posing a significant threat to human health and aquatic ecosystems. Conventional wastewater treatment methods often fail to eliminate ARGs, prompting the adoption of advanced oxidation processes (AOPs) to address this growing risk. The study investigates the efficacy of visible light-driven photocatalytic systems utilizing two catalyst types (TiO2-Pd/Cu and g-C3N4-Pd/Cu), with a particular emphasis on their effectiveness in eliminating bla TEM , ermB, qnrS, tetM. intl1, 16 S rDNA and 23 S rDNA through photocatalytic ozonation and peroxone processes. Incorporating O3 into photocatalytic processes significantly enhances target removal efficiency, with the photocatalyst-assisted peroxone process emerging as the most effective AOP. The reemergence of targeted contaminants following treatment highlights the pivotal importance of AOPs and the meticulous selection of catalysts in ensuring sustained treatment efficacy. Furthermore, Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis (PCR-DGGE) analysis reveals challenges in eradicating GC-rich bacteria with TiO2 and g-C3N4 processes, while slight differences in Cu/Pd loadings suggest g-C3N4-based ozonation improved antibacterial effectiveness. Terminal Restriction Fragment Length Polymorphism analysis highlights the efficacy of the photocatalyst-assisted peroxone process in treating diverse samples.

Environmental oligotrophic bacteria are suspected to be highly relevant carriers of antimicrobial resistance (AMR). However, there is a lack of validated methods for monitoring in the aquatic environment. Since extended-spectrum β-lactamases (ESBLs) play a particularly important role in the clinical sector, a culturing method based on R2A-medium spiked with different combinations of β-lactams was applied to quantify β-lactamase-producing environmental bacteria from surface waters. In German surface water samples (n = 28), oligotrophic bacteria ranging from 4.0 × 103 to 1.7 × 104 CFU per 100 mL were detected on the nutrient-poor medium spiked with 3rd generation cephalosporins and carbapenems. These numbers were 3 log10 higher compared to ESBL-producing Enterobacteriales of clinical relevance from the same water samples. A MALDI-TOF MS identification of the isolates demonstrated, that the method leads to the isolation of environmentally relevant strains with Pseudomonas, Flavobacterium, and Janthinobacterium being predominant β-lactam resistant genera. Subsequent micro-dilution antibiotic susceptibility tests (Micronaut-S test) confirmed the expression of β-lactamases. The qPCR analysis of surface waters DNA extracts showed the presence of β-lactamase genes (blaTEM, blaCMY-2, blaOXA-48, blaVIM-2, blaSHV, and blaNDM-1) at concentrations of 3.7 (±1.2) to 1.0 (±1.9) log10 gene copies per 100 mL. Overall, the results demonstrate a widespread distribution of cephalosporinase and carbapenemase enzymes in oligotrophic environmental bacteria that have to be considered as a reservoir of ARGs and contribute to the spread of antibiotic resistance.

Abstract Increasing carbon dioxide (CO2) concentration in the atmosphere is considered one of the most important challenges today. Therefore, capturing CO2 and producing alternative energy sources through Power-to-X (PtX) approaches have become relevant scientific topics in recent years. However, there is a significant research gap regarding water management in PtX processes, particularly in offshore operations. The present study evaluates relevant aspects and possible challenges with respect to water management as well as mass and energy balances in conceptual offshore methane and methanol production platforms. The results show that 1600 m3 of seawater must be desalinated to supply the electrolyzer and reach a daily 50-Megagram (Mg) hydrogen production. Around 1100 m3 of brine coming out of the desalination plant may be discharged to the sea as long as prior environmental impact assessments are conducted. Additionally, 273 Mg and 364 Mg CO2 need to be generated daily by direct air capture to produce 99 Mg day−1 methane and 265 Mg day−1 methanol, respectively. The daily produced methane and methanol wastewater is estimated to be 223 and 149 m3, respectively. Based on the scant literature on methanol wastewater, this is expected to contain toxic substances. Zero liquid discharge (ZLD) is proposed as wastewater method. The corresponding energy demand for the water management facilities is projected to be negligible compared to the other PtX processes. The presented management of water streams in PtX platforms would not only help recover some of the resources (water, hydrogen and methanol), but also substantially contribute to the production cycle itself while leading toward a more sustainable approach.

Lack of safe water availability and access to clean water cause a higher risk of infectious diseases and other diseases as well. Heavy metals (HMs) are inorganic pollutants that cause severe threats to humans, animals, and the environment. Therefore, an effective HM removal technology is urgently needed. In the present study, a customized bipolar membrane electrodialysis process was used to remove HMs from aqueous solutions. The impacts of the feed ionic strength, applied electrical potential, and the type and concentration of HMs (Cd2+, Co2+, Cr3+, Cu2+, and Ni2+) on the process performance were investigated. The results showed that feed solution pH changes occurred in four stages: it first decreased linearly before stabilizing in the acidic pH range, followed by an increase and stabilization in the basic range of the pH scale. HM speciation in the basic pH range revealed the presence of anionic HM species. The presence of HMs on anion exchange membranes confirmed the contribution of these membranes for HM removal in the base channels of the process. While no clear trend was seen in the ionic strength solution, the maximum HM removal was observed when 1.5 g/L NaCl was used. The initial HM concentration showed a linear increase in HMs removal of up to 30 mg/L. A similar trend was seen with an increase in the applied electrical potential of up to 15 V. In general, the amount of HMs removed increased in the following order: Cd2+ ˃ Ni2+ ˃ Co2+ ˃ Cu2+ ˃ Cr3+. Under some operational conditions, however, the removed amount of Cu2+, Co2+, and Ni2+ was similar. The mass balance and SEM-EDX results revealed that the removed HMs were sorbed onto the membranes. In conclusion, this process efficiently separates HMs from aqueous solutions. It showed the features of diluate pH adjustment, reduction in the overall stack electrical resistance, and contribution of anion exchange membranes in multivalent cation removal. The mechanisms involved in HMs removal were diffusion and migration from the bulk solution, followed by their sorption on both cation and anion exchange membranes.

Abstract Background Some microorganisms can respire with extracellular electron acceptors using an extended electron transport chain to the cell surface. This process can be applied in bioelectrochemical systems in which the organisms produce an electrical current by respiring with an anode as electron acceptor. These organisms apply flavin molecules as cofactors to facilitate one-electron transfer catalyzed by the terminal reductases and in some cases as endogenous electron shuttles. Results In the model organism Shewanella oneidensis, riboflavin production and excretion trigger a specific biofilm formation response that is initiated at a specific threshold concentration, similar to canonical quorum-sensing molecules. Riboflavin-mediated messaging is based on the overexpression of the gene encoding the putrescine decarboxylase speC which leads to posttranscriptional overproduction of proteins involved in biofilm formation. Using a model of growth-dependent riboflavin production under batch and biofilm growth conditions, the number of cells necessary to produce the threshold concentration per time was deduced. Furthermore, our results indicate that specific retention of riboflavin in the biofilm matrix leads to localized concentrations, which by far exceed the necessary threshold value. Conclusion This study describes a new quorum-sensing mechanism in S. oneidensis. Biofilm formation of S. oneidensis is induced by low concentrations of riboflavin resulting in an upregulation of the ornithine-decarboxylase speC. The results can be applied for the development of strains catalyzing increased current densities in bioelectrochemical systems.

Stricter environmental regulation policies and freshwater as an increasingly valuable resource have led to global growth of zero liquid discharge (ZLD) processes in recent years. During this development, in addition to water, the recovery of recyclable materials, e.g. salts, from industrial wastewater and brines is considered more frequently. Within the framework of the HighCon research project, the subject of this study, a new ZLD process with the goal of pure single-salt recovery from industrial wastewater has been developed and investigated in a demonstrational setup at an industrial site. With regard to pure salts recovery, separating organic components is of great importance during the treatment of the concentrate arising from used water recycling. The removal of COD and of ions responsible for scaling worked very well using nanofiltration. The nanofiltration permeate containing the monovalent ions was pre-concentrated using electrodialysis and membrane distillation before selective crystallization for single-salt recovery was performed. An example economic case study for the newly developed ZLD process – based on demonstration results and considering optimization measures for a full-scale design – indicates that the costs are equal to those of a conventional ZLD process, which, however, does not provide inter alia the aforementioned benefit of single-salt recovery. HIGHLIGHTS Stricter environmental regulation policies and freshwater as an increasingly valuable resource are leading to a global growth of zero liquid discharge (ZLD) processes in recent years.; In the study, the results of a demonstrational setup at an industrial site for a newly developed concentrate treatment process are presented. This new ZLD process, named HighCon, has the goal of pure single-salt recovery from industrial wastewater.; The demonstration results show that separating organic components and monovalent ions worked out very well with nanofiltration in the HighCon process and recovering an organic-free salt mixture or – using selective crystallization – the separation of an organic-free single salt with >90% purity has been enabled.; In a cost analysis, the total specific costs have been calculated for the newly developed HighCon process and a comparable ZLD process. With approximately 4 €/m³, the results show that the specific costs are in the same range for both processes.; The HighCon process has the advantage of pure (single-)salt recovery over conventional ZLD generating the mixture of solid wastes. Recovery of resources is becoming increasingly important – economically and with regard to the closing of recoverable substance cycles.;

Bivalent cations are known to affect the structural and mechanical properties of biofilms. In order to reveal the impact of Fe2+ ions within the cultivation medium on biofilm development, structure and stability, Bacillus subtilis biofilms were cultivated in mini-fluidic flow cells. Two different Fe2+ inflow concentrations (0.25 and 2.5 mg/L, respectively) and wall shear stress levels (0.05 and 0.27 Pa, respectively) were tested. Mesoscopic biofilm structure was determined daily in situ and non-invasively by means of optical coherence tomography. A set of ten structural parameters was used to quantify biofilm structure, its development and change. The study focused on characterizing biofilm structure and development at the mesoscale (mm-range). Therefore, biofilm replicates (n = 10) were cultivated and analyzed. Three hypotheses were defined in order to estimate the effect of Fe2+ inflow concentration and/or wall shear stress on biofilm development and structure, respectively. It was not the intention to investigate and describe the underlying mechanisms of iron incorporation as this would require a different set of tools applied at microscopic levels as well as the use of, i.e., omic approaches. Fe2+ addition influenced biofilm development (e.g., biofilm accumulation) and structure markedly. Experiments revealed the accumulation of FeO(OH) within the biofilm matrix and a positive correlation of Fe2+ inflow concentration and biofilm accumulation. In more detail, independent of the wall shear stress applied during cultivation, biofilms grew approximately four times thicker at 2.5 mg Fe2+/L (44.8 µmol/L; high inflow concentration) compared to the low Fe2+ inflow concentration of 0.25 mg Fe2+/L (4.48 µmol/L). This finding was statistically verified (Scheirer–Ray–Hare test, ANOVA) and hints at a higher stability of Bacillus subtilis biofilms (e.g., elevated cohesive and adhesive strength) when grown at elevated Fe2+ inflow concentrations.

The quantification of antibiotics (ABs) in sediments is an analytical challenge, but at the same time, it is indispensable to understand the fate of ABs in aquatic systems such as rivers. The aim of this study was to develop a comprehensive method to determine 19 ABs classified as macrolides, sulfonamides, fluoroquinolones, tetracyclines, clindamycin and trimethoprim in river sediments, using a combination of pressurized liquid extraction and solid phase extraction with the separation and detection with liquid chromatography coupled with mass spectrometry. Our results showed that the physical-chemical properties (e.g., log(Kow) value) of the analytes affected the extraction efficiency. Therefore, we propose to order ABs based on their log(Kow) values instead of traditional classification (macrolides, sulfonamides etc.) to select a suitable extraction solvent. ABs with log(Kow) values below zero (mainly fluoroquinolones and tetracyclines) were difficult to extract with all of the tested protocols compared to ABs with a log(Kow) larger than zero. After comparing different extraction protocols for ABs from solid and sediments, we concluded that recoveries in the range of 0.8 to 64.8% could be achieved for ABs with a log(Kow) value larger than zero using a mixture of acetonitrile and 50 mM phosphoric acid (50/50, v/v) in two extraction cycles at 100 °C.

Antimicrobial resistances are emerging as one main threat to worldwide human health and are expected to kill 10 million people by 2050. Intensive livestock husbandry, along with biogas digestate, are considered as one of the biggest ARG reservoirs. Despite major concerns, little information is available on the diversity and abundance of various ARGs in small to large scale pig farms and biogas digestate slurry in Germany, followed by their consequent removal using microfiltration (MF)–nanofiltration (NF) process. Here, we report the identification and quantification of 189 ARGs in raw manure and digestate samples, out of which 66 ARGs were shared among manures and 53 ARGs were shared among both manure and digestate samples. The highest reported total ARG copy numbers in a single manure sampling site was 1.15 × 108 copies/100 µL. In addition, we found the absolute concentrations of 37 ARGs were above 105 copies/100 μL. Filtration results showed that the highly concentrated ARGs (except aminoglycoside resistance ARGs) in feed presented high log retention value (LRV) from 3 to as high as 5 after the MF-NF process. Additionally, LRV below 2 was noticed where the initial absolute ARG concentrations were ≤103 copies/100 μL. Therefore, ARG removal was found to be directly proportional to its initial concentration in the raw manure and in digestate samples. Consequently, some ARGs (tetH, strB) can still be found within the permeate of NF with up to 104 copies/100 μL.

Intensive livestock farming has negatively impacted the environment by contributing to the release of ammonia and nitrous oxide, groundwater nitrate pollution and eutrophication of rivers and estuaries. The nitrogen footprint calculator has predicted the large impact of meat production on global nitrogen loss, but it could not form the relationship between meat production and the corresponding manure generation. Here we report on the formation of direct relationships between beef, pork and poultry meat production and the corresponding amount of nitrogen loss through manure. Consequently, the energy demand for ammonium nitrogen recovery from manure is also reported. Nitrogen loss to the environment per unit of meat production was found directly proportional to the virtual nitrogen factors. The relationship between total nitrogen intake and the corresponding nitrogen loss per kg of meat production was also found linear. Average nitrogen loss due to manure application was calculated at 110 g kg−1 for poultry. The average nitrogen loss increased to 190 and 370 g-N kg−1 for pork and beef productions, respectively. Additionally, 147 kg ammonium nitrogen was calculated to be recovered from 123 m3 of manure. This corresponded to 1 Mg of beef production. The recovery of ammonium nitrogen was reduced to 126 and 52 kg from 45 and 13 m3 of pork and poultry manure, respectively. The ammonium nitrogen recovery values were calculated with respect to 1 Mg of both pork and poultry meat productions. Consequently, the specific energy demand of ammonium nitrogen recovery from beef manure was noticed at 49 kWh kg−1, which was significantly 57% and 69% higher than that of pork and poultry manure, respectively.

This study aims to evaluate the application of ceramic ultrafiltration membranes in the crossflow mode for the separation of particles and oil in water emulsions (free oil droplets and micelles) from hydrothermal-liquefaction wastewater (HTL-WW) from the hydrothermal liquefaction of municipal sewage sludge. The experiments were carried out using one-channel TiO2 membranes with pore sizes of 30, 10 and 5 nm. The results showed that the highest stable permeability could be achieved with a membrane-pore size of 10 nm, which experienced less fouling, especially through pore blockage, in comparison to the two other pore sizes. Instead of observing an increase in the permeability, the application of a higher feed temperature as well as backwash cycles led to a clear increase in irreversible fouling due to the presence of surfactants in the HTL-WW. Among several physical and chemical cleaning methods, alkaline cleaning at pH 12 proved to be the most efficient in removing fouling and maintaining stable performance on a long-term basis. Ceramic-membrane ultrafiltration can be considered as an adequate first-stage treatment of real HTL wastewater.

The removal or degradation of particulate organic matter is a crucial part in biological wastewater treatment. This is even more valid with respect to aerobic granular sludge and the impact of particulate organic matter on the formation and stability of the entire granulation process. Before the organic part of the particulate matter can be hydrolyzed and finally degraded by the microorganism, the particles have to be transported towards and retained within the granulated biomass. The understanding of these processes is currently very limited. Thus, the present study aimed at visualizing the transport of particulate organic matter into and through an aerobic granular sludge bed. Magnetic Resonance Imaging (MRI) was successfully applied to resolve the different fractions of a granular sludge bed over time and space. Quantification and merging of 3D data sets allowed for a clear determination of the particle distribution within the granular sludge bed. Dextran coated super paramagnetic iron oxide nanoparticles (SPIONs, dp = 38±10 nm) served as model particles for colloidal particles. Microcrystalline cellulose particles (dp = 1–20 μm) tagged with paramagnetic iron oxide were applied as a reference for toilet paper, which is a major fraction of particulate matter in domestic wastewater. The results were supplemented by the use of real wastewater particles with a size fraction between 28 and 100 μm. Colloidal SPIONs distributed evenly over the granular sludge bed penetrating the granules up to 300 μm. Rinsing the granular sludge bed proved their immobilization. Microcrystalline cellulose and real wastewater particles in the micrometer range accumulated in the void space between settled granules. An almost full retention of the wastewater particles was observed within the first 20 mm of the granular sludge bed. Moreover, the formation of particle layers indicates that most of the micrometer-sized particles are not attached to the biomass and remain mobile. Consequently, these particles are released into the bulk phase when the granulated sludge bed is resuspended.

The livestock industry negatively impacts the environment by producing high organic and mineral loaded manure and wastewater. On the contrary, manure is also considered as the major focal point of resource recovery. The microfiltration (MF) process in manure treatment is well known for being the least complex and highly energy efficient. However, the major fraction of the dissolve nutrients easily bypasses the MF membranes. In this research work, we reported the efficiency of using MF–nanofiltration (NF) treatment train in a dead-end filtration system for the treatment of raw manure. The objectives were to produce nutrient rich separate streams in reduced volumes and a particle and pathogen-free product water. MF removed TSS above 98% and the COD and phosphorus (P) retention were noticed above 60 and 80%, respectively, within a reduced MF concentrate volume, which accounted for 40% of the initial feed volume. The NF of MF permeate by NF270 showed most promising results by concentrating overall 50 and 70% of the total nitrogen (TN) and potassium (K) within a reduced NF concentrate volume, which accounted for 30% of the initial MF feed volume. Finally, the MF–NF treatment train of raw pig manure could produce a particle-free product water that can be reused in farms to wash barns, to irrigate nearby cultures, or can be applied to specific fields based on the demand.

Abstract Background A future bioeconomy relies on the development of technologies to convert waste into valuable compounds. We present here an attempt to design a biotechnological cascade for the conversion of vegetable waste into acetoin and electrical energy. Results A vegetable waste dark fermentation effluent containing mainly acetate, butyrate and propionate was oxidized in a bioelectrochemical system. The achieved average current at a constant anode potential of 0 mV against standard hydrogen electrode was 177.5 ± 52.5 µA/cm2. During this step, acetate and butyrate were removed from the effluent while propionate was the major remaining component of the total organic carbon content comprising on average 75.6%. The key players with regard to carbon oxidation and electrode reduction were revealed using amplicon sequencing and metatranscriptomic analysis. Using nanofiltration, it was possible to concentrate the propionate in the effluent. The effluent was revealed to be a suitable medium for biotechnological production strains. As a proof of principle, the propionate in the effluent of the bioelectrochemical system was converted into the platform chemical acetoin with a carbon recovery of 86%. Conclusions To the best of our knowledge this is the first report on a full biotechnological production chain leading from vegetable waste to the production of a single valuable platform chemical that integrates carbon elimination steps leading to the production of the valuable side product electrical energy.

Biofilms growing on electrodes are the heart piece of bioelectrochemical systems (BES). Moreover, the biofilm morphology is key for the efficient performance of BES and must be monitored and controlled for a stable operation. For the industrial use of BES (i.e., microbial fuel cells for energy production), monitoring of the biofilm accumulation directly on the electrodes during operation is desirable. In this study a commercially available on-line heat transfer biofilm sensor is applied to a graphite-polypropylene (C-PP) pipe and compared to its standard version where the sensor is applied to a stainless-steel pipe. The aim was to investigate the transferability of the sensor to a carbonaceous material (C-PP), that are preferably used as electrode materials for bioelectrochemical systems, thereby enabling biofilm monitoring directly on the electrode surface. The sensor signal was correlated to the gravimetrically determined biofilm thickness in order to identify the sensitivity of the sensor for the detection and quantification of biofilm on both materials. Results confirmed the transferability of the sensor to the C-PP material, despite the sensor sensitivity being decreased by a factor of approx. 5 compared to the default biofilm sensor applied to a stainless-steel pipe.

Microorganisms settle in diverse partially saturated porous media in the form of biofilms. The alteration of hydraulic properties and diffusive transport processes occurs simultaneously with biofilm growth in porous media. Imaging methods offer the ability to directly visualize and quantify alterations on the pore scale. However, imaging methods have mainly observed biofilm growth in completely saturated porous media. The current study used magnetic resonance imaging (MRI) to dynamically visualize biofilm growth within a porous medium under alternating drainage and flushing events. Prior to the MRI experiments, the sample was cultivated for 6 days within a porous medium consisting of 2 mm glass spheres. Starting from day 6, growth was monitored using MRI over a period of 7 days. The approach allowed for a visualization of all fractions (biofilm, water, air, and porous material) after drainage as well as flushing events. Biofilm was found to preferentially grow within permanently wetted areas situated next to pore throats. Furthermore, an increase in the water retention and connectivity of the liquid phase was found. The largest liquid cluster covered 11% (day 6) and 91% (day 12) of the total retained water, suggesting that biofilm growth might improve diffusive transport processes within partially saturated porous media.

This work deals with the optimization of the concentration of volatile fatty acids (VFAs) using low-pressure reverse osmosis (LPRO) membranes. Membrane filtration of a synthetic solution simulating the product of biomass hydrolysis was performed. Experiments were run on two flat-sheet XLE membranes under 22 and 25 bar in continuous operation mode. Separation efficiency was evaluated for different recoveries. A correlation between the osmotic pressure of the concentrate and the parameter Rc, representative of the separation efficiency, was found. Under the conditions of the present study and taking into consideration the rejection properties of the applied membrane, a recovery of 33% and 44% is recommendable to maximize the ratio between the concentration of acetate in the concentrate and permeate and thus increase the total reclaim of acetic acid.

Due to the fact, that microplastics are a global environmental problem, new ways for their removal from water, soil and air need to be developed. New materials in combination with easy to implement technologies for microplastic removal come into the focus of scientific studies and engineering, especially for application in water resources. In our comparative case study, the effects of water composition and temperature on the agglomeration-fixation reaction of microplastics using organosilanes were examined. We compared biologically treated municipal wastewater, seawater and demineralized water at temperatures ranging from 7.5–40 °C. Temperature variations and tested water compositions showed no negative effect on microplastic removal. The residues of the organosilanes remaining in the water after the fixation process were monitored using ICP-OES and DOC measurements. Only one of the organosilanes tested showed no dissolved residues in the waters. Microplastic encompasses a multitude of different types of polymers with different properties and surface chemistries. Therefore, we compared the efficiency of the process for polyethylene, polypropylene, polyamide, polyester, and polyvinylchloride as examples of common polymer types with different chemical compositions. A strong effect of the polarity of microplastics and organosilanes on removal efficiency was observed. The organic groups of organosilanes can be chemically adapted to different polymer types.

Polyether sulfone Multibore® ultrafiltration membranes were modified using polyelectrolyte multilayers via the layer-by-layer (LbL) technique in order to increase their rejection capabilities towards salts and antibiotic resistance genes. The modified capillary membranes were characterized to exhibit a molecular weight cut-off (at 90% rejection) of 384 Da. The zeta-potential at pH 7 was −40 mV. Laboratory tests using single-fiber modified membrane modules were performed to evaluate the removal of antibiotic resistance genes; the LbL-coated membranes were able to completely retain DNA fragments from 90 to 1500 nt in length. Furthermore, the pure water permeability and the retention of single inorganic salts, MgSO4, CaCl2 and NaCl, were measured using a mini-plant testing unit. The modified membranes had a retention of 80% toward MgSO4 and CaCl2 salts, and 23% in case of NaCl. The modified membranes were also found to be stable against mechanical backwashing (up to 80 LMH) and chemical regeneration (in acidic conditions and basic/oxidizing conditions).

The biotechnological usage of carbon dioxide has become a relevant aim for future processes. Microbial electrosynthesis is a rather new technique to energize biological CO2 fixation with the advantage to establish a continuous process based on a cathodic biofilm that is supplied with renewable electrical energy as electron and energy source. In this study, the recently characterized cathodic biofilm forming microorganism Kyrpidia spormannii strain EA-1 was used in an adaptive laboratory evolution experiment to enhance its cathodic biofilm growth capabilities. At the end of the experiment, the adapted cathodic population exhibited an up to fourfold higher biofilm accumulation rate, as well as faster substratum coverage and a more uniform biofilm morphology compared to the progenitor strain. Genomic variant analysis revealed a genomically heterogeneous population with genetic variations occurring to various extends throughout the community. Via the conducted analysis we identified possible targets for future genetic engineering with the aim to further optimize cathodic growth. Moreover, the results assist in elucidating the underlying processes that enable cathodic biofilm formation.

This study aimed to investigate the effects of sludge retention time (SRT), hydraulic retention time (HRT), and biomass concentration (CTSS) in activated sludge systems on removal of various micropollutants (MPs), covering a wide spectrum of biodegradability. The influence of biomass concentration on the classical pseudo-first-order rate constant was verified. Results showed that the removal rate constants were affected by both the HRT and SRT. The enhancement of the SRT increased the removal of all the MPs except for two macrolide antibiotics. Application of a higher HRT also improved MP removal, as was expected from the measured removal rate constants. More interesting, our results indicated that, logically, the increase of biomass concentration (expressed as total suspended solids CTSS) from 3 to 5 gTSS L−1 significantly enhanced the removal rate of the highly and moderately degradable compounds. Conversely, a further increase to 8 gTSS L−1 produced only an unexpected moderate effect, showing that the rate was not proportional to biomass concentration, contrary to what is generally postulated. Therefore, the use of classical kinetic models is questionable, since they do not cover the entire range of boundary conditions in activated sludge systems. This work opens new research paths and suggests potential improvements to processes.

Application of solar photocatalysis for water treatment is intensively studied. In this work, we investigated TiO2 modified with platinum (Pt/TiO2) and palladium (Pd/TiO2) using sulfamethoxazole (SMX) as the model contaminant. We considered the following parameters: (i) level of TiO2 modification with Pt/Pd, (ii) initial concentration of photocatalysts, (iii) geographic location where processes were conducted, and (iv) natural water matrix. The catalysts characterized by SEM, EDX, DRS, and XRD techniques showed successful deposition of Pd and Pt atoms on TiO2 surface that enabled light absorption in the visible (Vis) range, and therefore caused efficient SMX removal in all tested conditions. A comparison of the rate constants of SMX degradation in various conditions revealed that modification with Pd gave better results than modification with Pt, which was explained by the better optical properties of Pd/TiO2. The removal of SMX was higher with Pd/TiO2 than with Pt/TiO2, independent of the modification level. In the experiments with the same modification level, similar rate constants were achieved when four times the lower concentration of Pd/TiO2 was used as compared with Pt/TiO2. Formation of four SMX transformation products was confirmed, in which both amine groups are involved in photocatalytic oxidation. No toxic effect of post-reaction solutions towards Lepidium sativum was observed.

This work aimed to develop a new economic enzymatic process to treat the phenolic pollutants using pure tyrosinase in stirred vessel and adopting temperature (T), pH, rotational speed (N), initial phenol (C P,o) and enzyme (C T) concentrations as independent variables. Experimental data of the residual phenol concentration (C P) were used to calculate the oxidation efficiency (η), initial oxidation rate (-r o) and time required to reach the end of reaction (t) that were selected as the responses. Under the optimal conditions (T = 45°C, pH 6.6, N = 400 rpm, C P,o = 100 ppm and C T = 50 U/mL), η was 88.1%, -r o = 10.2 mg L-1 min-1, t = 40 min. These results suggested that tyrosinase-rich crude extracts from vegetable byproducts could be quite promising.

Abstract The insulin-like growth factor 2 mRNA binding protein 1 (IGF2BP1) is a conserved RNA-binding protein that regulates RNA stability, localization and translation. IGF2BP1 is part of various ribonucleoprotein (RNP) condensates. However, the mechanism that regulates its assembly into condensates remains unknown. By using proteomics, we demonstrate that phosphorylation of IGF2BP1 at S181 in a disordered linker is regulated in a stress-dependent manner. Phosphomimetic mutations in two disordered linkers, S181E and Y396E, modulate RNP condensate formation by IGF2BP1 without impacting its binding affinity for RNA. Intriguingly, the S181E mutant, which lies in linker 1, impairs IGF2BP1 condensate formation in vitro and in cells, whereas a Y396E mutant in the second linker increases condensate size and dynamics. Structural approaches show that the first linker binds RNAs nonspecifically through its RGG/RG motif, an interaction weakened in the S181E mutant. Notably, linker 2 interacts with IGF2BP1’s folded domains and these interactions are partially impaired in the Y396E mutant. Importantly, the phosphomimetic mutants impact IGF2BP1’s interaction with RNAs and remodel the transcriptome in cells. Our data reveal how phosphorylation modulates low-affinity interaction networks in disordered linkers to regulate RNP condensate formation and RNA metabolism.