Using single-cell level seeding and separate culture system for the isolation of electrochemically active bacteria
Screening electrochemically active bacteria is of great significance for understanding biogeochemical cycles and developing bioelectrochemical systems.At present,the screening of electrochemically active bacteria primarily involves enrichment and isolation-verification methods.However,the high selectivity of culture conditions for dominant strains makes it difficult to isolate low-abundance,non-dominant electrochemically active bacteria,thus reducing the diversity of acquired strains.To address this,a single-cell level seeding and separate culture system for electrochemically active bacteria was developed to minimize the influence of interspecies competition and improve screening throughput and efficiency.This method involves isolating microorganisms at the single-cell level through limited dilution and controlled droplet volume,followed by anaerobic cultivation.The electrochemical activity is indicated using the color changing indicator of electron acceptor WO3.We used the anode biofilm of a bioelectrochemistry system as the screening source and 31 electrochemically active strains were isolated from 352 culture wells.These strains belong to the genera Geobacter,Geosporobacter,Azonexus,Sinanaerobacter,Clostridium,Thauera,and Azoarcus.In the testing of bioelectrochemical systems,the isolated strains could use the anode as electron acceptor,with redox peaks obtained in cyclic voltammetry tests.This study establishes a simple and high-throughput single-cell level isolation and screening method for electrochemically active bacteria,providing a significant advancement in the resource mining of electrochemically active bacteria.
anaerobicsingle-cell level seedingseparate cultureextracellular electron transferelectrochemically active bacteria
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