FG Biotechnologie der Wasseraufbereitung
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The long-term application of immobilized quorum quenching (QQ) bacteria requires carrier materials with sufficient mechanical stability and durability across various operating conditions. This study aims to enhance the durability and stability of polyvinyl alcohol (PVA) beads and to evaluate their performance for long-term operation. The beads were synthesized using two PVA brands with different molecular weights (MWs), and the effect of cross-linking conditions and reagent purity on bead stability was also investigated. Primarily, their physical strength was evaluated under centrifugal forces. Additionally, polyvinyl alcohol and sodium alginate (PVA-SA) beads were incorporated with cellulose to enhance their strength. The structural and chemical characteristics of the beads were examined using scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR). The results showed that PVA 100 kDa beads withstood centrifugal forces up to 11,000 rpm without breakage, whereas lower MW (PVA 85 kDa) beads failed at 5000 rpm. Bead quality was critically sensitive to calcium chloride purity, as impurities and reduced Ca2+ availability caused poor crosslinking and structural collapse. The results revealed that PVA 100 kDa increases the number of polymer chain entanglements and intermolecular interactions, which enhance the structural integrity. Bead quality is strongly influenced by the purity of calcium chloride in the crosslinking solution, as well as by the solution pH. SEM analysis showed that cellulose-incorporating beads exhibited a denser and more uniform pore structure, with median equivalent pore diameters reduced from 50 µm (PVA-SA) to 22.4 µm upon cellulose incorporation, while maintaining sufficient porosity for nutrient diffusion. Similarly, FTIR analysis confirmed that cellulose was successfully integrated, with increased hydroxyl interactions and modified C–O vibrational characteristics, indicating strong hydrogen bonding within the composite matrix. Principal component analysis (PCA) confirmed that hydroxyl interactions and C–O vibrational modes are the main contributors to spectral variation, indicating that cellulose acts as a structural modifier in the PVA-SA network. These results demonstrate the effectiveness of this strategy in designing durable PVA-SA-cellulose based composite beads for long-term QQ applications.
Biofouling remains a critical challenge in membrane bioreactors (MBR), which is primarily caused by the production of extracellular polymeric substances (EPS) as an initial step in biofilm formation. This still limits their widespread application in wastewater treatment. In the past decades, much research has been carried out to understand and consequently reduce biofouling in MBR. More recent studies have focused primarily on inhibiting the release of EPS by applying quorum quenching (QQ) to control biofouling in MBR. This study presents the first investigation of the QQ potential of Rubellimicrobium mesophilum and its effects on biofilm inhibition by EPS reduction, which is demonstrated for MBR operated with submerged flat sheet (PTFE, PS) and hollow fibre polyvinylidene fluoride (PVDF) membranes operated in parallel for 114 days. The QQ effect has a significant impact on the reduction of biofilm thickness on PTFE membranes by 45% and on PS membranes by about 47% respectively. Additionally, the performance of PVDF was improved by 287.5%. Similarly, the total protein concentration on the PTFE membranes was reduced by 57%, while on the PS membranes, the reduction was 78%. In mixed liquor, protein reduction was 55%, indicating its effectiveness in controlling biofouling over extended operation. The biofilm formation was monitored by measuring the biofilm thickness via fluorescence microscopy and by analyzing the protein and sugar content of the developing biofilm and of the mixed liquor. All parameters proved a decreasing biofilm formation with increasing amounts of entrapped QQ bacteria, while the removal efficiency of organic compounds and ammonia remained similar between all MBRs.
Synergistic enhancement of PFOA and 6:2-FTAB photodegradation using Au/Y-doped TiO2 nanocatalysts
(2026)
Efficient degradation of perfluoroalkyl substances (PFAS) requires photocatalysts capable of promoting strong CF bond cleavage and selective interfacial charge transfer. In this proof-of-concept-study, a dual-doped TiO2 nanophotocatalyst (Au2/Y5/P25) was synthesized by combining gold (Au) nanoparticles and yttrium (Y) dopants to enhance charge separation and reactive oxygen species (ROS) generation. Structural characterization supported Au deposition on the TiO2 surface and Y incorporation into the lattice, accompanied by a slight bandgap narrowing. Under UV irradiation in aqueous solution (unbuffered pH 5.8, room temperature) the nanophotocatalyst exhibited distinct degradation pathways for 1000 μg L-1 of two representative PFAS, perfluorooctanoic acid (PFOA) and Capstone B (6:2 FTAB), reflecting environmentally prevalent groups. PFOA underwent 99 % degradation within 100 min via a stepwise CF2-cleavage mechanism, generating a sequence of perfluorocarboxylic acids down to perfluorobutanoic acid (PFBA), consistent with enhanced electron-hole separation. In contrast, Capstone B showed rapid, single-step S-N bond cleavage to 6:2 perfluorooctanesulfonic acid (6:2 PFOS), primarily driven by hole- and •OH-mediated oxidation under oxygen-rich conditions. This process achieved 96 % degradation within 20 min but did not proceed to further defluorination, indicating oxidative limitations. Dissolved oxygen analysis revealed efficient electron utilization and sustained oxidative turnover without excessive oxygen depletion. The findings demonstrate that Au/Y co-doping promotes selective PFAS activation, enabling rapid precursor oxidation while exposing the kinetic limits of secondary C-F bond cleavage. These discoveries offer new insights into the design of plasmonic-rare-earth-modified TiO2 photocatalysts for efficient PFAS degradation through interface-driven oxidation pathways.
Quorum quenching (QQ) is a promising biological approach that has the potential to control membrane biofouling. However, the implementation of the QQ membrane bioreactor still requires a more systematic and comprehensive understanding, including the selection of membrane materials, the determination of the optimal QQ bacterial dosage, and the use of appropriate media for the immobilization of QQ bacteria, all of which are important to ensure long-term operation. The present study investigated the impact of QQ bacteria on biofilm formation across different polymeric membranes. These include flat sheet membranes, Polytetrafluoroethylene (PTFE), Polysulfones (PSs), and hollow-fibre polyvinylidene difluoride (PVDF) membranes. It also evaluated biofilm development, membrane filtration performance, extracellular polymeric substance (EPS) production, and sludge floc properties, which were characterized using fluorescence microscopy. The results revealed that QQ intervention markedly suppressed quorum sensing (QS), leading to a pronounced, dose-dependent reduction in biofilm thickness, membrane fouling, EPS production and sludge floc size. Biofilm thickness was reduced by 63.5% on PTFE and 55.4% on PS membranes, accompanied by a notable reduction in EPS protein and polysaccharides, thereby weakening the biofilm formation and enhancing membrane filterability. Therefore, the permeability performance of the PVDF membrane improved by 338.2%. Furthermore, sludge settleability was enhanced, and floc size was reduced, resulting in the mitigation of biofilm formation without impacting pollutant degradation. These findings elucidate the material-dependent and dose-responsive mechanism by which QQ regulates EPS synthesis and biofilm formation in MBR.
In this study, we investigated the impact of varying iron (Fe) and aluminum (Al) contents on the adsorption of phosphonates to activated sludge. Phosphonates originating from household applications account for up to 40% of the non-reactive dissolved phosphorus in domestic sewage treatment plants and thus can contribute to the eutrophication of water bodies. Although these substances are not readily degradable, substantial quantities, ranging from 40% to more than 90%, are removed by sludge adsorption. The results demonstrate a strong correlation between the adsorption of aminophosphonates and the Fe3+ content of the sludge. The maximum phosphonate loadings were 5.94 mmol g−1 Fe3+ for ATMP, 4.94 mmol g−1 Fe3+ for EDTMP, 4.74 mmol g−1 Fe3+ for DTPMP, and 2.25 mmol g−1 Fe3+ for glyphosate. In contrast to pure ferric hydride flocs, the adsorption of phosphonates was approximately threefold higher when the hydroxides were located within activated sludge flocs. It is concluded that native sludge flocs provide larger iron surfaces than ferric hydroxide alone. Based on the weight of the adsorbents, aluminum salts were four times less efficient than ferric salts. In sludge without ferric or aluminum hydroxides, phosphonate adsorption was negligible.
Direct dependence on surface water poses a threat to human health when consumed without treatment. While solar water disinfection treatment systems (SODIS) help improve the quality of surface water for rural households, SODIS approaches, implementation, and adoption have some limitations. Consequently, this study developed a hybrid water disinfection treatment system at the laboratory scale, integrating novel Advanced Oxidation Processes (AOP). Additionally, surface water quality, the challenges, and enablers of effective implementation of SODIS in rural Ghana were assessed. Two hybrid disinfection systems in continuous flow with reactor volumes of 300 ml each were operated. The disinfection of Staphylococcus aureus in the hybrid disinfection system achieved a 99.60% reduction at 360 min, while complete disinfection (100%) was achieved with photocatalyst integration without regrowth after post-treatment storage for 24 hr. A proportionate 96.24% disinfection rate was achieved for Salmonella senftenberg within 360 min in the hybrid disinfection system while 100% disinfection was achieved with the integration of a photocatalyst. Similarly, no regrowth of Salmonella senftenberg was observed after 24 hr post-treatment storage. The disinfection of Bacillus subtilis was optimized from 95.46% in the hybrid treatment system to 99.99% in the hybrid system with photocatalyst within 360 min. Furthermore, a disinfection proportion of 99.97% was achieved in the hybrid system at 360 min, while 100% disinfection was achieved with the hybrid disinfection system at 300 min for Escherichia coli with the integration of photocatalyst. No Escherichia coli re-growth was observed after a 24 hr post treatment storage. The water quality index generated based on the surface water quality assessment showed that all surface water sources are polluted largely due to total and faecal coliforms. The results proved that SODIS can serve as a suitable water treatment approach for adoption in the Sawla-Tuna-Kalba (STK) District. Out of 1155 respondents, 97% of the respondents are willing to accept and adopt a SODIS. Based on the findings, the enablers of effective SODIS implementation were willingness to pay for SODIS, household and community participation, and willingness to use water from SODIS. The identified barriers to the implementation of SODIS were environmental, technological, political and legal, and economic barriers. Compositional and contextual factors such as age, marital status, education, religion, and geographical location significantly mediate and attenuate households’ willingness to accept and adopt SODIS in the STK District of Ghana.
In this study, several professional cleaning products were analyzed for their impact on local air and sewage contamination. The products were first analyzed for their content of potentially harmful ingredients, their biodegradability, and the potential for the mobilization of hazardous substances from the floorings that were cleaned. The contribution of the cleaning products to sewage pollution with environmentally hazardous substances was studied at full scale. All commercially available cleaning products studied were declared to be environmentally friendly (labeled with the EU Ecolabel). However, despite being labeled as “green” products, between 16 and 24 volatile harmful ingredients were identified. An optimized experimental product, produced completely from natural raw materials, also contained several harmful substances originating from the herbal raw materials themselves. During the field study, we identified a range of trace substances in the sewage. Eight of these substances (e.g., p-cymene, butanone, eucalyptol) significantly originated from the cleaning products. Several others may have originated from the cleaning products, but other sources were also possible. The flooring materials that were cleaned contained several harmful substances themselves. The release of some substances (e.g., toluene) into the sewage significantly increased during the cleaning process.
Colorectal cancer (CRC) ranks third in men and second in women, with 153,020 new cases and 52,550 deaths in 2023, and with a projected incidence of 2.2 million new cases by 2030 due to lifestyle changes and enhanced diagnostic capabilities. Identification and analysis of new biomarkers, like lens epithelium-derived growth factor splice variant of 75 kDa (LEDGF/p75), which is known to play a crucial role as stress-related oncogene, can make a significant contribution in facilitating early CRC detection. This study analyzed the expression of LEDGF/p75 and the ubiquitin E2 conjugating enzyme UBC13 in 15 CRC tissue samples and adjacent non-tumor tissues. All patient samples underwent NGS-based mutation analysis beforehand. The western blot technique was used for protein analysis, and the results were further validated using mRNA expression data from 521 patient samples from the TCGA database. LEDGF/p75 expression was significantly elevated in nearly all tumor tissue samples compared to adjacent tissue (11/15, 73.3%). Additionally, the UBC13 enzyme, a key regulator in the degradation of signaling molecules, was also increased in most tumor tissue samples (9/15, 60.0%). Co-overexpression of LEDGF/p75 and UBC13 was evident in 6/6 patients. Patients with KRAS and MSH2 mutations showed a 75% and 100% correlation with LEDGF/p75 overexpression, respectively. This study confirms the upregulation of LEDGF/p75 in CRC and shows its correlation with KRAS and MSH2 mutations. The interaction of LEDGF/p75 with DNA damage response proteins may contribute to drug resistance and increased tumor aggressiveness. LEDGF/p75’s potential as a prognostic biomarker independent of lymph node involvement or CEA levels highlights its potential in personalized therapy, and warrants further research into its therapeutic targeting.
The consumption of contaminated water contributes to the global burden of diarrhea and other water-borne diseases, especially among young children. While decentralized solar water disinfection treatment systems (hereafter SODIS) remain a viable option to have safe drinking water, our understanding of the effects of household water treatment before use on willingness to accept and adopt a SODIS is limited. In this study, a complementary log-log regression analysis of the compositional and contextual factors that systematically vary with willingness to accept and adopt a SODIS in the Sawla-Tuna-Kalba (STK) district of Ghana was carried out. Based on our findings, a greater proportion of households (97%) are willing to accept and adopt a SODIS. Compositional and contextual factors such as age, marital status, education, religion, and geographical location significantly contribute to households’ willingness to accept and adopt a SODIS in the STK district of Ghana. Households that treat their water before use (66%, p < 0.05) are more likely to accept and adopt a SODIS compared to those that do not treat their water before use. The findings, therefore, suggest that scaling up SODIS in the STK district is sacrosanct and highlight the necessity to analyse compositional and contextual factors influencing willingness to accept and adopt SODIS. Our findings will inform policies and programs aimed at implementing SODIS in the study area to improve the health of communities that rely on poor-quality drinking water sources.
Laundry isolate Delftia sp. UBM14 capable of biodegrading industrially relevant aminophosphonates
(2024)
Phosphonates such as ethylenediaminetetra (methylenephosphonic acid) (EDTMP) and aminotris (methylenephosphonic acid) (ATMP) are used every day in water treatment processes or in household products. Their consumption is still increasing, regardless of the debates on their environmental impact. Here, the microbial characterisation and determination of the biodegradation potential of selected industrially relevant phosphonates for the isolate Delftia sp. UMB14 is reported. The opportunistic strain was isolated from a biofilm that was derived from a conventional washing machine using conventional detergents containing phosphonates. In antimicrobial susceptibility testing, the strain was only susceptible to sulfonamide, tetracycline, and chloramphenicol. Physiological and biochemical characteristics were determined using the BIOLOG EcoPlate assay. Most importantly, the strain was shown to convert D-malic acid and D-mannitol, as confirmed for strains of Delftia lacustris, and thus the new isolate could be closely related. Biodegradation tests with different phosphonates showed that the strain preferentially degrades ATMP and EDTMP but does not degrade glyphosate (GS) and amino (methylphosphonic acid) (AMPA). A specific gene amplification confirmed the presence of phnX (phosphonoacetaldehyde hydrolase) and the absence of PhnJ (the gene for the core component of C–P lyase). The presence of PhnCDE is strongly suggested for the strain, as it is common in Delftia lacustris species.
