Influence of support materials on the electroactive behavior, structure and gene expression of wild type and GSU1771-deficient mutant of Geobacter sulfurreducens biofilms.

Geobacter sulfurreducens DL1 is a metal-reducing dissimilatory bacterium frequently used to produce electricity in bioelectrochemical systems (BES). The biofilm formed on electrodes is one of the most important factors for efficient electron transfer; this is possible due to the production of type IV pili and c-type cytochromes that allow it to carry out extracellular electron transfer (EET) to final acceptors. In this study, we analyzed the biofilm formed on different support materials (glass, hematite (FeO) on glass, fluorine-doped tin oxide (FTO) semiconductor glass, FeO on FTO, graphite, and stainless steel) by G.

Global transcriptional analysis of Geobacter sulfurreducens gsu1771 mutant biofilm grown on two different support structures.

Electroactive biofilms formation by the metal-reducing bacterium Geobacter sulfurreducens is a step crucial for bioelectricity generation and bioremediation. The transcriptional regulator GSU1771 controls the expression of essential genes involved in electron transfer and biofilm formation in G. sulfurreducens, with GSU1771-deficient producing thicker and more electroactive biofilms.

GSU1771 regulates extracellular electron transfer and electroactive biofilm formation in Geobacter sulfurreducens: Genetic and electrochemical characterization.

Type IV pili and the >100c-type cytochromes in Geobacter sulfurreducens are essential for extracellular electron transfer (EET) towards metal oxides and electrodes. A previous report about a mutation in the gsu1771 gene indicated an enhanced reduction of insoluble Fe(III) oxides coupled with increased pilA expression. Herein, a marker-free gsu1771-deficient mutant was constructed and characterized to assess the role of this regulator in EET and the formation of electroactive biofilms.