Elongated Riboflavin‐Producing Shewanellaoneidensis in a Hybrid Biofilm Boosts Extracellular Electron Transfer

Abstract

Shewanella oneidensis is able to carry out extracellular electron transfer (EET), although its EET efficiency is largely limited by low flavin concentrations, poor biofilm forming‐ability, and weak biofilm conductivity. After identifying an important role for riboflavin (RF) in EET via in vitro experiments, the synthesis of RF is directed to 837.74 ± 11.42 µm in S. oneidensis. Molecular dynamics simulation reveals RF as a cofactor that binds strongly to the outer membrane cytochrome MtrC, which is correspondingly further overexpressed to enhance EET. Then the cell division inhibitor sulA, which dramatically enhanced the thickness and biomass of biofilm increased by 155% and 77%, respectively, is overexpressed. To reduce reaction overpotential due to biofilm thickness, a spider‐web‐like hybrid biofilm comprising RF, multiwalled carbon nanotubes (MWCNTs), and graphene oxide (GO) with adsorption‐optimized elongated S. oneidensis, achieve a 77.83‐fold increase in power (3736 mW m−2) relative to MR‐1 and dramatically reduce the charge‐transfer resistance and boosted biofilm electroactivity. This work provides an elegant paradigm to boost EET based on a synthetic biology strategy and materials science strategy, opens up further opportunities for other electrogenic bacteria.

Microbial Electrochemical Systems and Membrane Bioreactor Technology for Wastewater Treatment

“…The EET is classified into two types depending on how the extracellular electrons are transferred from the adherent microorganisms (biofilm) to the anode electrode, so no additional electroactive metabolites are required for electrons transfer, but the presence of electroactive organisms is the primary factor. Previous researchers have reported several species of EABs, including Shewanella [28,29], Rhodoferax [30,31], and Geobacteraceae [32,33]. Other species of EABs have used mediator-based electroactive secreted metabolites or artificial redox compounds for electron transport [26].…”

Efficient Enhancement of Extracellular Electron Transfer in Shewanella oneidensis MR-1 via CRISPR-Mediated Transposase Technology

“…The extracellular electron-transfer (EET) capability of Shewanella oneidensis MR-1 has shown promising applications in various fields, such as energy recovery and ecological restoration. − For MR-1, the EET mechanism and efficiency, collectively termed microbial electroactivity, are fundamental determining factors influencing its application potential and performance. , However, the low EET efficiency remains a key limiting factor in its practical application. To address this issue, numerous studies have concentrated on engineering or optimizing various pathways and associated genes involved in the EET of MR-1. , Typical approaches include molecular biological modifications of membrane-bound c-type cytochromes (c-Cyts) and conductive pili (e-pili), , enhanced biosynthesis and transport of flavins, , and improved biofilm formation abilities. , Additionally, the emergence of decoupled exogenous pathways and systematic multipathway genetic reconstruction aims to overcome existing bottlenecks, such as the NADH decoupling pathway …”

Coproduction of Bioelectricity and Acetoin by Unbalanced Fermentation of Glycerol in Shewanella oneidensis Based on a Genome-Scale Metabolic Network

“…In recent years, carbon-based nanomaterials (e.g., carbon nanotubes and graphene) have become research hot spots in various fields because of their excellent properties. Zhao et al constructed a functional anode comprising riboflavin, multiwalled carbon nanotubes, and graphene oxide, achieving 3736 mW m –2 power density and dramatically boosting the power density …”

“…Zhao et al constructed a functional anode comprising riboflavin, multiwalled carbon nanotubes, and graphene oxide, achieving 3736 mW m −2 power density and dramatically boosting the power density. 11 Genome-scale metabolic models (GEMs) are mature and effective methods to mathematically express and simulate the metabolic network in an organism from a systematic perspective, which can effectively integrate various omics information of cells and promote the understanding and analysis of cell behavior from the system level. 12 GEMs have been widely applied to determine metabolic engineering targets in well-studied chassis cells (such as Escherichia coli, Saccharomyces cerevisiae, etc.).…”