MOE Key Laboratory of Pollution Processes and Environmental Criteria / Tianjin Key Laboratory of Environmental Remediation and Pollution Control / College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin, 300350, China.
School of Environmental Science and Engineering, Tianjin University, No. 92 Weijin Road, Nankai District, Tianjin, 300072, China.
Water Res. 2020 Jun 15;177:115776. doi: 10.1016/j.watres.2020.115776. Epub 2020 Apr 7.
Bioelectrochemical systems (BESs) are widely investigated as a promising technology to recover bioenergy or synthesize value-added products from wastewaters. The performance of BES depends on the activity of electroactive biofilm (EAB). As the core of BES, it is still unclear how the EAB is formed from mixed inoculum, and how exoelectrogens compete with non-exoelectrogens. Here we confirmed that microbial community composition and the morphology of EAB on the electrode including the thickness and porosity of the biofilm are critical for the performance of BES, and these properties can be simply controlled by the substrate concentration during EAB formation. The EAB formed with 0.1 g/L of acetate (EAB-0.1) exhibited a 90% higher current density than that formed with 1.0 g/L acetate (EAB-1.0). EAB-0.1 had a 50% higher electroactivity per biomass and a 20% thinner thickness than EAB-1.0, which was partly due to the 54% decrease of insulative polysaccharide in biofilm. Limited acetate also imposed a selective pressure to enrich Geobacter up to 88% compared to 72% when acetate was abundant. Our findings demonstrate that a highly active EAB can be formed by limiting substrate concentration, providing a broader understanding of the EAB formation process, the ecology of interspecies competitions and potential applications for bioenergy recovery and trace toxicant detection in the future.
生物电化学系统 (BES) 作为从废水中回收生物能源或合成增值产品的一种很有前途的技术而被广泛研究。BES 的性能取决于电活性生物膜 (EAB) 的活性。作为 BES 的核心，EAB 如何从混合接种物中形成，以及外电子体如何与非外电子体竞争，目前仍不清楚。在这里，我们证实了微生物群落组成和电极上 EAB 的形态（包括生物膜的厚度和孔隙率）对 BES 的性能至关重要，并且这些特性可以通过 EAB 形成过程中基质浓度简单地控制。以 0.1 g/L 乙酸（EAB-0.1）形成的 EAB 的电流密度比以 1.0 g/L 乙酸（EAB-1.0）形成的 EAB 高 90%。EAB-0.1 的生物量电化学活性比 EAB-1.0 高 50%，厚度比 EAB-1.0 薄 20%，这部分是由于生物膜中绝缘性多糖减少了 54%。有限的乙酸也对丰度达 88%的地杆菌施加了选择性压力，而当乙酸丰富时，地杆菌的丰度为 72%。我们的研究结果表明，通过限制基质浓度可以形成高活性的 EAB，这为深入了解 EAB 的形成过程、种间竞争的生态学以及未来在生物能源回收和痕量有毒物质检测方面的潜在应用提供了更广泛的认识。
