Electrobiocorrosion by microbes without outer-surface cytochromes.

Anaerobic microbial corrosion of iron-containing metals causes extensive economic damage. Some microbes are capable of direct metal-to-microbe electron transfer (electrobiocorrosion), but the prevalence of electrobiocorrosion among diverse methanogens and acetogens is poorly understood because of a lack of tools for their genetic manipulation. Previous studies have suggested that respiration with 316L  stainless steel as the electron donor is indicative of electrobiocorrosion, because, unlike pure Fe, 316L  stainless steel does not abiotically generate H as an intermediary electron carrier.

Cytochrome-mediated direct electron uptake from metallic iron by .

Methane-producing microorganisms accelerate the corrosion of iron-containing metals. Previous studies have inferred that some methanogens might directly accept electrons from Fe(0), but when this possibility was more intensively investigated, H was shown to be an intermediary electron carrier between Fe(0) and methanogens. Here, we report that catalyzes direct metal-to-microbe electron transfer to support methane production.

Different outer membrane -type cytochromes are involved in direct interspecies electron transfer to or species.

Direct interspecies electron transfer (DIET) may be most important in methanogenic environments, but mechanistic studies of DIET to date have primarily focused on cocultures in which fumarate was the terminal electron acceptor. To better understand DIET with methanogens, the transcriptome of during DIET-based growth with reducing fumarate was compared with grown in coculture with diverse . The transcriptome of cocultured with was significantly different from those with .