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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. [ABSTRACT FROM AUTHOR]

5-Aminolevulinic acid (5-ALA) has recently received much attention for its wide applications in medicine and agriculture. In this study, we investigated the effect of NCgl0580 in Corynebacterium glutamicum on 5-ALA biosynthesis as well as its possible mechanism. It was found that the overexpression of NCgl0580 increased 5-ALA production by approximately 53.3%. Interestingly, the knockout of this gene led to an even more significant 2.49-fold increase in 5-ALA production. According to transcriptome analysis and functional validation of phenotype-related targets, the deletion of NCgl0580 brought about considerable changes in the transcript levels of genes involved in central carbon metabolism, leading to fluxes redistribution toward the 5-ALA precursor succinyl-CoA as well as ATP-binding cassette (ABC) transporters affecting 5-ALA biosynthesis. In particular, the positive effects of enhanced sugar transport (by overexpressing NCgl1445 and iolT1), glycolysis (by overexpressing pyk2), iron uptake (by overexpressing afuABC), and phosphate uptake (by overexpressing pstSCAB and ugpQ) on 5-ALA biosynthesis were demonstrated for the first time. Thus, the transcriptional mechanism underlying the effect of NCgl0580 deletion on 5-ALA biosynthesis was elucidated, providing new strategies to regulate the metabolic network of C. glutamicum to achieve a further increase in 5-ALA production. [ABSTRACT FROM AUTHOR]

Microbial fuel cells (MFCs), unique biosystems that generate energy through exoelectrogens, have undergone significant development in the last decades. Although MFCs have great prospects in environmental protection and power generation, there are still problems of inefficiency and high cost, which are largely attributed to the low performance of anode materials used in MFCs because the anode plays a crucial role in MFCs as a carrier for microbial attachment. In the last few years, researchers have shown great interest in developing advanced anode materials to enhance the performance of MFCs. Herein, an overview of recent progress in the development of anode materials for MFCs is offered. In addition, novel anode modification strategies are summarized. Finally, challenges and development directions of next‐generation anode materials with the potential to finally enable the commercial application of MFCs are discussed. [ABSTRACT FROM AUTHOR]

Malodorous black water body is always with high organic contents under extreme anaerobic conditions and has pungent smell. With the large amount of living pollution entering rivers and lakes, water eutrophication occurs, and the water body gradually evolves into malodorous black water body, which seriously affects the safety of water quality and the health of humans. Biochemical method has been considered as the most economical and efficient method for the treatment of malodorous black water body. In this study, the directional screening technology of bacterial biofilm was used for the first time, and a variety of degrading strains of malodorous black water were obtained from various heavily polluted waters. Ammonia nitrogen removal efficiency of three strains was more than 60%, and the Chemical Oxygen Demand (COD) removal efficiency was over 75%. Through the mixed culture of the three kinds of bacteria, the removal efficiency can be improved. Optimized degradation conditions of mixed bacteria were as follows: with pH of 7, dissolved oxygen concentration of 2.5 mg/L, temperature of 30°C, the total bacterial concentration of 15%, the initial COD of around 50 mg/L, and the initial ammonia nitrogen of about 17 mg/L. Ammonia nitrogen and COD were totally degraded in 50 h, and total phosphorus degradation efficiency was also more than 80%. This research provides novel insights for the treatment of malodorous black water. [ABSTRACT FROM AUTHOR]