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Direct interspecies electron transfer (DIET) is essential for maintaining the function and stability of anaerobic microbial consortia. However, only limited natural DIET modes have been identified and DIET engineering remains highly challenging. In this study, an unnatural DIET between Shewanella oneidensis MR‐1 (SO, electron donating partner) and Rhodopseudomonas palustris (RP, electron accepting partner) was artificially established by a facile living cell‐cell click chemistry strategy. By introducing alkyne‐ or azide‐modified monosaccharides onto the cell outer surface of the target species, precise covalent connections between different species in high proximity were realized through a fast click chemistry reaction. Remarkably, upon covalent connection, outer cell surface C‐type cytochromes mediated DIET between SO and RP was achieved and identified, although this was never realized naturally. Moreover, this connection directly shifted the natural H2 mediated interspecies electron transfer (MIET) to DIET between SO and RP, which delivered superior interspecies electron exchange efficiency. Therefore, this work demonstrated a naturally unachievable DIET and an unprecedented MIET shift to DIET accomplished by cell‐cell distance engineering, offering an efficient and versatile solution for DIET engineering, which extends our understanding of DIET and opens up new avenues for DIET exploration and applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Shewanella loihica PV-4 exhibited high performance in reducing CO 2 to formate. • A novel three-dimensional biological self-assembled cathode was constructed. • No involvement of electron mediators was found in whole cell catalysis. • Faraday efficiency of bioelectrosynthetic CO 2 -to-formate reached 99.95%. Bioelectrochemical CO 2 reduction (bio-CO 2 R) provides a sustainable and carbon neutral power-to-chemical route. Whole-cell electrosynthesis is one of the attractive strategies to realize CO 2 R due to its simple and low-cost superiorities. However, it is still challenging to overcome the sluggish transmembrane electron transfer of microorganisms without exogenously added mediators. Here, we described the fabrication of biohydrogel that contains bio-reduced graphene oxide (rGO) and living electroactive bacteria (EAB) for bio-CO 2 R. The EAB exhibited surprising ability to self-assemble biohydrogel that was further served as biocathode to drive CO 2 -to-formate electrosynthesis. With the close interaction between EAB and rGO nanosheets, the transmembrane electron transfer achieved at high Faradaic efficiency (∼99.5 %) and 46-fold increase of formate titer without exogenous mediator. This work provided the facile and practical approach to bridge the bacterial cell and electrode for efficient electron transfer and implied the new possibility to store the electric energy into chemicals with bio-CO 2 R. [ABSTRACT FROM AUTHOR]