Univ Lyon, Ecole Centrale de Lyon, INSA Lyon, Université Claude Bernard Lyon 1, CNRS, Ampère, UMR5005, 69130, Ecully, France; Universite Claude Bernard Lyon 1, Laboratoire d'Ecologie Microbienne, UMR CNRS 5557, UMR INRAE 1418, VetAgro Sup, 69622, Villeurbanne, France.
Universite Claude Bernard Lyon 1, Laboratoire d'Ecologie Microbienne, UMR CNRS 5557, UMR INRAE 1418, VetAgro Sup, 69622, Villeurbanne, France.
Biosens Bioelectron. 2024 Jan 15;244:115806. doi: 10.1016/j.bios.2023.115806. Epub 2023 Nov 5.
This study has provided comprehensive insights into the intricate relationship between shear stress and the development, structure, and functionality of electroactive biofilms in Microbial Fuel Cells (MFCs). A multichannel microfluidic MFC reactors that created specific shear stress on the anode, were designed for the simultaneous study of multiple flow conditions using the same medium. Then, the evolution of the biofilm growth under different shear stress conditions (1, 5 and 10 mPa) were compared. The taxonomic and functional structure was studied by 16S rRNA gene and metagenomic sequencing and the physical biofilm characteristics were measured via fluorescence microscopy. The results demonstrate the pivotal role of shear stress in influencing the growth kinetics, electrical performance, and physical structure of anodic biofilms. Notably, the selection of specific EAB was observed to be shear stress-dependent, with a marked increase in specific EAB abundance as shear stress increased. The power density, while not directly correlated with the relative abundance of specific or nonspecific EAB, exhibited a strong linear relationship with biofilm coverage. This suggests that factors beyond the microbial composition, potentially including mass transport or electrochemical conditions, might be instrumental in determining electricity production. The functional metagenomic analysis further highlighted the complexities of extracellular electron transfer (EET) mechanisms in electroactive biofilm. While certain genes associated with EET in known species such as Geobacter and Shewanella were identified, the study also examined the limitations of solely relying on genetic markers to infer EET capabilities, emphasizing the need for complementary metaproteomic analyses. This study demonstrates the multifaceted impact of shear stress on electroactive biofilm and paves the way for future investigations aimed at harnessing the potential of electroactive biofilms in microbial fuel cell applications.
本研究全面深入地探讨了切应力与电活性生物膜在微生物燃料电池（MFC）中的发展、结构和功能之间的复杂关系。为了同时研究多种流动条件，设计了一种在阳极上产生特定切应力的多通道微流体 MFC 反应器，该反应器使用相同的介质。然后，比较了在不同切应力条件（1、5 和 10 mPa）下生物膜生长的演变。通过 16S rRNA 基因和宏基因组测序研究了分类和功能结构，并通过荧光显微镜测量了物理生物膜特性。结果表明，切应力在影响阳极生物膜的生长动力学、电性能和物理结构方面起着关键作用。值得注意的是，观察到特定 EAB 的选择取决于切应力，随着切应力的增加，特定 EAB 的丰度明显增加。功率密度虽然与特定或非特定 EAB 的相对丰度没有直接关系，但与生物膜覆盖率呈强线性关系。这表明，决定发电的因素可能超出微生物组成，包括传质或电化学条件。功能宏基因组分析进一步强调了电活性生物膜中细胞外电子转移（EET）机制的复杂性。虽然确定了与已知物种（如 Geobacter 和 Shewanella）中的 EET 相关的某些基因，但该研究还考察了仅依赖遗传标记推断 EET 能力的局限性，强调了需要进行补充的代谢组学分析。本研究表明了切应力对电活性生物膜的多方面影响，为未来旨在利用微生物燃料电池应用中电活性生物膜潜力的研究铺平了道路。
