Polyphasic Characterization of Geotalea uranireducens NIT-SL11 Newly Isolated from a Complex of Sewage Sludge and Microbially Reduced Graphene Oxide.

Graphene oxide (GO), a chemically oxidized sheet of graphite, has been used as a conductive carbon carrier of microbes to boost various bioelectrochemical reactions. However, the types of microbes that can reduce GO have rarely been investigated. In this study, a strain of GO-reducing bacteria, named NIT-SL11, which was obtained from a hydrogel of microbially reduced GO and anaerobic sludge that converts sewage to electricity, was phylogenically identified as a novel strain of . Considering the current lack of information on the electrogenic ability of the bacterium and its physicochemical and chemotaxonomic characteristics, the polyphasic characterization of the strain NIT-SL11 was performed. NIT-SL11 utilized various organic acids, such as lactate, benzoate, and formate, as electron donors and exhibited respiration using GO, electrodes, fumarate, and malate. The strain contained C16:1ω7c and C16:0 as the major fatty acids and MK-8 and 9 as the major respiratory quinones. The complete genome of NIT-SL11 was 4.7 Mbp in size with a G+C content of 60.9%, and it encoded 80 putative c-type cytochromes and 23 type IV pili-related proteins. The possible extracellular electron transfer (EET) pathways of the strain were the porin-cytochrome (Pcc) EET pathway and type IV pili-based pathway.