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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 15 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Advancing microbial electrolysis cells (MECs) for efficient wastewater-to-energy conversion(2026); The global energy crisis and fossil fuel impacts highlight the need for sustainable energy carriers such as hydrogen. Microbial electrolysis cells (MECs) can generate hydrogen from organic waste, but their optimization under complex feedstock conditions remains challenging. Accordingly, this study focused on optimizing key parameters to enhance MEC performance. Variation in flow velocity (0.2 and 0.8 mm/s) in Geobacter sulfurreducens and Shewanella oneidensis co-culture biofilms, cultivated in a microfluidic bioelectrochemical system, showed that S. oneidensis exhibited a pronounced flow-dependent response. Higher shear stress produced thinner but more electroactive biofilms, linked to biofilm formation through mechanosensing pathways. To further evaluate system performance, the effects of substrate concentration (20–60%), pH (5–8), and applied anodic potential (−0.2 to +0.4 V vs standard hydrogen electrode [SHE]), in a cylindrical microbial electrolysis cell (Cylindrical-MEC) were also studied. Optimal performance was achieved at 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 95 %. Metagenomic and PCA analyses revealed that high anodic potential and alkaline pH enriched Geobacter-dominated communities while suppressing methanogens. In a 10-L rotating disk bioelectrochemical reactor (RDBER), operation at 0.4 V vs. SHE achieved a hydrogen production rate of 30.57 L/m²·d with minimal methane formation. The hydrogen produced under these conditions was subsequently utilized for the autotrophic synthesis of acetoin.Publicationtype: Doctoral Thesis45 17