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Item type:Publication, Access status: with files , Selective bioelectrochemical purification of propionate from food waste hydrolysate(Elsevier, 2026-12-21); ; Dark fermentation enables hydrogen production while generating propionate-rich streams from food waste. However, efficient separation of propionate from short-chain fatty acid (SCFA) mixtures remains challenging and costly in the downstream processes. Therefore, strategies enabling selective purification of propionate prior to separation from the fermentation broth are highly desirable. In this study, a bioelectrochemically assisted bench-scale process was developed as a proof-of-concept pretreatment to enhance selective purification of propionate prior to downstream processing. A single-chamber rotating disc bioelectrochemical reactor (RDBER) was used to selectively purify the hydrolysate via enhancing the consumption of butyrate by an electroactive biofilm of a recently published butyrate-oxidizing microbial consortium. In the RDBER, different hydraulic retention times (HRTs) without and with pH control were evaluated to investigate their effects on propionate fraction among SCFAs and process stability. The results show that with a pH of 7.0–7.3 and an HRT of 8 days, a propionate fraction of up to 95.5% can be achieved, with its concentration doubling compared to the feed. These results demonstrate the potential of this process as a pretreatment step prior to downstream separation, with the aim of reducing separation complexity and enhancing propionate recovery.Publicationtype: Journal Article15 7 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Flow-driven structural and transcriptomic responses in syntrophic electroactive biofilms(Elsevier, 2026-07-07); ; ; ; Bioelectrochemical systems (BES) are versatile platforms for energy and resource recovery, where electroactive biofilms serve as the key biocatalyst. While performance depends on flow dynamics, the interplay between hydrodynamic conditions, biofilm architecture, and gene-regulation in syntrophic communities remains poorly understood. We investigated defined surface flow velocities (0.2 and 0.8 mm/s) on the structure and electroactivity of Shewanella oneidensis–Geobacter sulfurreducens coculture biofilms. Higher flow produced more compact biofilms with lower biovolume and porosity, yielding higher current densities. Flow transitions induced persistent structural and electrochemical shifts, indicating an adaptive, gene-regulated response to shear. Since G. sulfurreducens monoculture biofilms were flow-insensitive, regulation appears to originate from S. oneidensis. Transcriptomics showed strong shear response, including 10.7-fold upregulation of bpfD. Its deletion reduced current density and increased porosity despite comparable biovolume. Three-dimensional fluorescence in situ hybridization imaging revealed a porous, loosely organized structure within the mutant biofilm. This was consistent with the structural and electrochemical differences observed. These findings reveal that community-level electrochemical performance can be governed by a minor transcriptional contributor rather than by the dominant current-producing species.Publicationtype: Journal Article15 6 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Tuning membraneless microbial electrolysis cells operation alters efficiency and anodic microbiome toward scalable hydrogen production from sludge-hydrolysate(Elsevier, 2026-01-21); ; ; ; The practical implementation of microbial electrolysis cells (MECs) is hindered by challenges in optimizing system performance with complex substrates. This study addresses that gap by evaluating MECs fed with hydrolysate, an appealing substrate rich in organic-acids. Through systematic variation of substrate concentration (20–60 %), pH (5–8), and applied anodic potential ( 0.2 to +0.4 V vs standard hydrogen electrode [SHE]), the optimal operational conditions were defined as 40 %-hydrolysate, pH 8, and +0.4 V vs SHE, yielding a mean current density of 3.4 A/m2 and coulombic efficiencies (CE) of 38 % and 96 % based on total organic carbon (TOC) and total volatile fatty acids (VFAs), respectively. Scalability was demonstrated using a 10 L rotating disk bioelectrochemical reactor (RDBER) at 0 and 0.4 V vs SHE, achieving a maximum hydrogen production rate of 30.57 L/m2/d and minimal methane formation at 0.4 V. These findings offer a framework for optimizing MECs under real-feedstock conditions.Publicationtype: Journal Article33 16 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , EBPR process dynamics under variable conditions: interaction between PAOs and the microbial communityThe performance of enhanced biological phosphorus removal (EBPR) is influenced by various process conditions, such as the type of carbon source, temperature, COD:P ratio or pH-value. The activity of polyphosphate accumulating organisms (PAOs) and the composition of biocoenosis are strongly influenced by these process conditions. Nevertheless, critical knowledge gaps remain regarding the relevance of microbial diversity and the correlations between PAO/GAO community composition and EBPR process dynamics under different operational conditions. This study demonstrates that Dechloromonas plays a crucial role in the EBPR process and that the type of carbon source has a more sensitive influence on EBPR dynamics than the COD:P ratio, temperature or pH. Using both a microfluidic model biofilm system (MMBS) and a sequencing batch reactor (SBR) system, we found that the consumption of glucose resulted in maximal PAO activity, whereas EBPR performance was limited when using glycerol, ethanol and amino acids. In both systems, Dechloromonas was the dominant PAO, while in MMBS Zoogloea and in SBR Competibacter/Contendobacter were the dominant GAOs. Tessaracoccus (PAO) and Micropruina (GAO) were relevant in the fermentation of glucose and glycerol. No significant effect on EBPR performance was observed between 12 and 20 °C, and PAO activity peaked at pH 7.5. Our findings highlight that PAO-GAO competition is overestimated. We anticipate that our study provides a deeper understanding of the dynamics in the biocoenosis and emphasizes the relevance of biodiversity in EBPR systems, which would help guide relevant applications.Publicationtype: Journal Article15 15 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Qualitatively elucidating the molecular characteristics of precursors for saturated halogenated disinfection byproducts in chlorinated urban eutrophic lake water by ultrahigh-resolution mass spectrometryLake eutrophication affects the molecular composition of aquatic dissolved organic matter (DOM) and halogenated disinfection byproducts (Xn-DBPs). However, the effects of autochthonous DOM on the Xn-DBPs formation during disinfection of natural eutrophic water from the perspective of biological metabolism are still poorly revealed. Herein, the natural urban eutrophic lake (UEL) water with slight eutrophication was employed to elucidate the discrepancies in Xn-DBPs formation between autochthonous and allochthonous DOM based on the ultrahigh-resolution mass spectrometry. The number and its proportion of nitrogenous Xn-DBPs in chlorinated UEL water samples were significantly larger (p < 0.05) than those for chlorinated SRNOM. Microbes dominated by Microcystis contributed largely to releasing autochthonous DOM for Xn-DBPs formation upon disinfection. The Xn-DBPs species mainly derived from microorganisms were highly saturated, reduced, bioavailable, nitrogenous, and toxic but lowly oxidized and aromatic than terrestrially derived Xn-DBPs species. Moreover, for the first time, the connection between microbial lipid metabolism and Xn-DBPs species exclusively identified in chlorinated UEL water indicated the considerable contribution of lipid metabolites to saturated Xn-DBPs species. The specific biochemical mechanism of Xn-DBPs formation from autochthonous DOM caused by the lysis of microbe cells highlighted the significant contribution of microbial metabolic activities, particularly lipid metabolism, to the generation of highly saturated and nitrogenous Xn-DBPs during chlorination. This study has also reported a novel data interpretation paradigm for Xn-DBPs research, deepening our understanding towards the formation mechanisms of microbe-derived Xn-DBPs species from the view of microbial metabolic pathways.Publicationtype: Journal Article17 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Illuminating bioprocess responses to metal-based nanoparticles addition along hydrogen and methane production pathways : a review(Elsevier, 2025); ; ; ; Abdelaziz, Omar Y.Recent research has discussed the positive impacts of metal-based nanoparticles (NPs) on bioprocesses producing either hydrogen (H2) or methane (CH4). The enhancement has been explained by mechanisms such as direct interspecies electron transfer (DIET), metal corrosion, and dissimilatory reduction. Such interactions could induce further benefits, such as controlling oxidation–reduction potential (ORP), mitigating toxicants, promoting enzymatic activity, and altering the microbiome, which have not yet been comprehensively discussed. Factors like metal type, oxidation state, and size of NPs are crucial for their reactivity and corresponding responses. This review discusses how different redox potentials of metals can regulate metabolic pathways and how NPs and their reactive ions can eliminate toxicants (e.g., sulfate) and enhance the activity of intra- and extracellular enzymes. The enrichment of responsive microorganisms in correlation with NPs is further discussed. A better understanding of the multifaceted role of metal-based NPs can guide potential new incorporation strategies to improve bioprocesses.Publicationtype: Review Article10 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Efficacious enrichment of butyrate-oxidizing exoelectrogens upgrades energy recovery in relevant bioelectrochemical systems(Elsevier, 2024-11-01); ; ; ; Energy recovery via bioelectrochemical systems (BESs) while treating organic wastes has proven to be a promising technology. Organic waste hydrolysates are appealing feedstocks for BESs due to their richness in short-chain fatty acids rather than complex organics. However, butyrate, among the abundant acids in hydrolysates, has been found to particularly hinder the efficiency of BESs. The lack of efficient anodic butyrate-oxidizers appears to be critical; therefore, this study targeted the enrichment of an anodic community to enhance butyrate oxidation efficiency in BESs. We initially tested three different inoculum sources using butyrate as the sole electron donor. Then, through successive transfers of a bioanode piece to fresh anodes, significant improvement in coulombic efficiency (CE) from 9.4 % to 78.6 % was achieved over six transfers. The enriched bioanode was dominated by the bacterial genera Geobacter (72 %) and Sporomusa (16 %), which correlated positively with CE development over transfers. The metagenomic/transcriptomic analyses confirmed the key role of Geobacter in the anodic oxidation of butyrate, while Sporomusa likely displayed a syntrophic interaction, assimilating acetate from CO2 and excess H2. The enriched culture was further bioaugmented with Geobacter sulfurreducens and tested with real butyrate-containing hydrolysate, in which CE and maximum current density of 86.9 % and ∼3.5 A/m2 were achieved, respectively. Overall, the enriched butyrate-oxidizing culture, bioaugmented with G. sulfurreducens, proves efficient for BESs treating butyrate-rich waste-streams.Publicationtype: Journal Article13 22 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Incorporating concrete waste as additive in acidic fermentation – a novel approach for enhanced biohydrogen production and concrete mass reduction(Elsevier, 2024-10-16); ; ; Acidic fermentation (AF) of organic waste/wastewater generates valuable byproducts, including hydrogen, volatile fatty acids, and ethanol; however, its sensitivity to pH drops limits the stability and efficiency of the process. A reversal process, the acidic chemical treatment of concrete waste (CW) to recycle its aggregates, generates calcium hydroxide, which can serve as buffering agent. Meanwhile, integrating both processes can introduce a sustainable win-win approach, which is the aim of this study. To assess this approach, a series of batch AF experiments were conducted at 50 °C and pH 5.5, using glucose as the substrate. Cementitious specimen (1.5 × 1.5 × 0.8 cm) was supplemented to each 200 mL-fermenter. Unamended fermenters, with and without additional NaHCO3-buffering, were used as controls to compare with the amended ones. Introducing cementitious specimens to AF increased H2-production by 2-fold and 1.7-fold compared to controls with and without NaHCO3-addition, respectively, after three consecutive feed-cycles. The surface analysis of incorporated specimen confirmed the Ca, Al, Mg, and Si leaching. The AF efficiency and resulting cementitious mass reduction were further assessed at different organic loads and specimens’ volume, surface area, and porosity (by changing water-to-cement [W/C] ratio). Increasing the organic load from 10 to 20 g-glucose/L resulted in lower H2-production, higher specimen mass reduction (up to ∼32%), and higher Ca2+ release (up to 2 g/L); however, no significant effect was observed when using specimens with higher W/C ratio or surface area. Moreover, the presence of cementitious specimens significantly influenced the microbial composition, leading to notable developments in the abundant genera Thermoanaerobacterium and Bacillus. This study presents a novel approach to sustainably enhancing AF process using CW as both an additive and a treatable substance, with reusable aggregates as a byproduct. It provides valuable insights for optimizing the process and guiding future practical applications. This includes considering various concrete compositions, adjusting organic load conditions, and evaluating long-term stability in larger-scale systems.Publicationtype: Journal Article18 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Impacts of micro- to nano-sized carbon supplements on mixed and archaea-free halophilic cultures when used for bioenergy recovery from saline wastewaterDue to the growing interest in enhancing dark fermentation and anaerobic digestion via carbon-based additives to exploit different lucrative synergies, process-based optimizations and mechanistic analyses are crucial. Herein, we studied the impacts of carbon supplements on halophilic microbial cultures as a process intensification way towards bioenergy recovery from saline wastewater. Three additives, i.e., powdered activated carbon, multiwall carbon nanotubes and graphene, were examined. Two sets of parallel batch experiments were conducted using archaea-free (for dark fermentation) and mixed (for anaerobic digestion) halophilic cultures at different supplement doses. Adding 30 mg/L of graphene and 100 mg/L of powdered activated carbon exhibited the maximum improvements in dark fermentation (H2-production) and anaerobic digestion (biogas production), i.e., ∼28% and ∼27% over the control, respectively. This underscored the dose-dependent impact of different-sized carbon amendments. Both the electron transport system activity and extracellular polymeric substances were improved with all amendments, indicating a stimulated electron transfer flux. However, distinct bacterial compositions were identified when using mixed and archaea-free cultures along with indicators for direct interspecies electron transfer establishment in the presence of archaea. Beyond this, such findings also supported the expanded role of conductive additives on H2-producing bacteria, including Clostridium. According to a techno-economic analysis, powdered activated carbon emerged as the best for optimizing bioenergy recovery (in terms of H2 or biogas) from saline wastewater, providing a solid basis for relevant applications.Publicationtype: Journal Article13 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Probing the robustness of Geobacter sulfurreducens against fermentation hydrolysate for uses in bioelectrochemical systemsIn this study, impacts of toxic ions/acids found in real fermentation-hydrolysate on the model exoelectrogenic G. sulfurreducens were investigated. Initially, different concentrations of acetate, butyrate, propionate, Na+, and K+ were tested, individually and in combination, for effects on the planktonic growth, followed by validation with diluted-hydrolysate. Meanwhile, it could be shown that (1) excess Na+ (≥100 mM) causes inhibition that can be reduced by K+ replacement, (2) butyrate (≥10 mM) induces higher toxicity than propionate, and (3) hydrolysate induces synergistic inhibition to G. sulfurreducens where organic constituents contributed more than Na+. Afterwards, compared with impacts on planktonic cells, the pre-enriched anodic biofilm of G. sulfurreducens in BESs showed higher robustness against diluted-hydrolysate, achieving current densities of 1.4–1.7 A/m2 (at up to ∼30 mM butyrate and propionate as well as ∼240 mM Na+). As a conclusion, using G. sulfurreducens in BESs dealing with fermentation-hydrolysate can be regulated for efficacious energy recovery.Publicationtype: Journal ArticleScopus© Citations 3 39