The accumulation of macro-, micro- and nano-plastic wastes in the environment is a major global concern, as these materials are resilient to degradation processes. However, microorganisms have evolved their own biological means to metabolize these petroleum-derived polymers, e.g., Ideonella sakaiensis has recently been found to be capable of utilizing polyethylene terephthalate (PET) as its sole carbon source. This study aims to prove its potential capacity to biodegrade two commercial PET materials, obtained from food packaging containers. Plastic pieces of different crystallinity were simultaneously introduced to Ideonella sakaiensis during a seven-week lasting investigation. Loss in weight, appearance of plastics, as well as growth of Ideonella sakaiensis—through quantitative real-time PCR—were determined. Both plastics were found enzymatically attacked in a two-stage degradation process, reaching biodegradation capacities of up to 96%. Interestingly, the transparent, high crystallinity PET was almost fully degraded first, followed by the colored low-crystallinity PET. Results of quantitative real-time PCR-based gene copy numbers were found in line with experimental results, thus underlining its potential of this method to be applied in future studies with Ideonella sakaiensis.

The increasing research in the field of polymeric multi-channel membranes has shown that their mechanical stability is beneficial for a wide range of applications. The more complex interplay of formation process parameters compared to a single-channel geometry makes an investigation using Design of Experiments (DoE) appealing. In this study, seven-channel capillary membranes were fabricated in a steam–dry–wet spinning process, while varying the composition of the polymer solution and the process temperatures in a three-level fractional factorial linear screening design. The polymers polyvinylidene flouride (PVDF) was the chemically resistant main polymer and polyvinylpyrrolidone (PVP) was added as hydrophilic co-polymer. Scanning electron microscopy and atomic force microscopy were applied to study the membrane morphology. Fabrication process conditions were established to yield PVDF/PVP multi-channel membranes, which reached from high flux (permeability P = $321.4$ $\mathrm{L}$ / ${\mathrm{m}}^2$ / $\mathrm{h}$ /bar, dextran 500 $\mathrm{kDa}$ retention R = 18.3%) to high retention (P = $66.8$ $\mathrm{L}$ / ${\mathrm{m}}^2$ / $\mathrm{h}$ /bar, R = 80.0%). The concentration of the main polymer PVDF and the molecular weight of the co-polymer PVP showed linear relations with both P and R. The permeability could be increased using sodium hypochlorite post-treatment, although retention was slightly compromised. The obtained membranes may be suitable for micro- or ultra-filtration and, at the same time, demonstrate the merits and limitations of DoE for multi-channel membrane screening.

The mechanical stability of conventional single-channel capillary fibres can be improved in a multi-channel geometry, which has previously found application in ultrafiltration. In this work, multi-channel polyethersulfone (PES) capillary membranes comprising seven feed channels were successfully fabricated in an enhanced steam–dry–wet spinning process and coated on the inner surface with a thin polyamide (PA) layer via interfacial polymerization (IP). The coating procedure consisted of impregnating the support multi-channel capillary membranes (MCM) with an aqueous piperazine solution, flushing with nitrogen gas to remove excess droplets, and pumping an organic trimesoylchloride solution through the channels. Insights into the interfacial polymerization process were gained through the investigation of various parameters, including monomer ratio, contact time, and drying time. Membranes were characterised via scanning electron microscopy (SEM), atomic force microscopy (AFM), and filtration experiments. The optimisation of both the PES support membrane and IP process parameters allowed for the fabrication of composite MCM with an MgSO₄ rejection of 91.4% and a solute flux of 68.8 L m⁻² h⁻¹ at an applied pressure of 3 bar. The fabricated composite MCM demonstrates that a favourable multi-channel arrangement can be upgraded with a PA layer for application in low-pressure nanofiltration.

Antimicrobial resistance genes threaten the effective treatment of infectious diseases, underscoring the importance of their control in line with the EU One Health policy. Wastewater treatment plants are recognized hotspots for antimicrobial resistance. We assessed whether multi-channel mixed-matrix membranes (MCMMMs)—polyethersulfone (PES)/polyvinylpyrrolidone (PVP) ultrafiltration membranes with embedded activated carbon—can concurrently reduce microorganisms and extracellular DNA in wastewater effluent, building on prior reports of micropollutant removal. We evaluated the performance of MCMMMs in removing Escherichia coli and Saccharomyces cerevisiae as model organisms, as well as colony-forming units (CFUs) from wastewater effluent at a transmembrane pressure of 1 bar with a filtration area of 66 cm² over 1 h. DNA was extracted from wastewater effluent following filtration and analyzed to assess changes in microbial community composition. MCMMMs achieved log₁₀ reductions of 5.47 ± 0.42 (Escherichia coli), 5.99 ± 0.46 (Saccharomyces cerevisiae), and 2.79 ± 0.31 (wastewater CFU); reductions by pure PES/PVP membranes were comparable: higher for Escherichia coli and wastewater CFUs, lower for Saccharomyces cerevisiae. Amplicon sequencing showed altered relative abundances in wastewater effluent. Collectively, these findings demonstrate the potential of MCMMMs to simultaneously remove microorganisms, extracellular DNA, and micropollutants, highlighting their suitability for water treatment applications within the One Health framework.