Acetate limitation selects Geobacter from mixed inoculum and reduces polysaccharide in electroactive biofilm. (15th June 2020)

• Record Type: Journal Article
• Authors: Li, Tian; Zhou, Qixing; Zhou, Lean; Yan, Yuqing; Liao, Chengmei; Wan, Lili; An, Jingkun; Li, Nan; Wang, Xin
• Is Part Of: Water research. Volume 177(2020)
• Publication Date: 2020-06-15
• Subjects: Bioelectrochemical systems -- Substrate limitation -- Electroactivity -- Extracellular cytochromes -- Microbial community; Water -- Pollution -- Research -- Periodicals; 363.7394
• DOI: 10.1016/j.watres.2020.115776
• Languages: English
• ISSNs: 0043-1354

Abstract

Abstract: 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. Graphical abstract: Image 1 Highlights: Electroactive biofilm (EAB) growing at limited acetate produced 90% more current. Limited acetate selectively enriched Geobacter . Limited acetate decreased the secretion of insulative polysaccharide in biofilm. EAB at limited acetate had a 50% higher electroactivity and a 20% thinner biofilm.