An electricity-generating prosthecate bacterium strain Mfc52 isolated from a microbial fuel cell

Area of Science:

• Microbiology
• Bioelectrochemistry
• Environmental Science

Background:

• Alphaproteobacteria with prosthecae are abundant in cellulose-fed microbial fuel cell (MFC) biofilms.
• The ecological role of these bacteria in MFCs is not well understood.

Purpose of the Study:

• To isolate and characterize a novel bacterium from MFC biofilms.
• To elucidate the ecological role of this bacterium in electricity generation within MFCs.

Main Methods:

• Isolation of strain Mfc52 from MFC anode biofilm.
• Phylogenetic analysis for taxonomic classification.
• Fermentation and growth experiments with varying substrates (glucose, ferric ion).
• Electricity generation experiments in MFCs inoculated with strain Mfc52.
• Electron microscopy to observe cell morphology, including prosthecae.

Main Results:

• Strain Mfc52, a deeply branched Alphaproteobacteria possibly representing a novel order, was isolated.
• Strain Mfc52 ferments sugars to lactate, acetate, and fumarate, with growth stimulated by ferric ion.
• MFCs inoculated with strain Mfc52 and glucose generated electricity through the oxidation of glucose-derived organic acids.
• Prosthecae-like appendages were observed on a fraction of cultured cells, consistent with biofilm observations.

Conclusions:

• Strain Mfc52 occupies a significant niche in cellulose-fed MFCs.
• This bacterium generates electricity by oxidizing intermediate metabolites from cellulose degradation.
• The presence of prosthecae may be linked to its function in the MFC anode biofilm.