Plugging in or going wireless: strategies for interspecies electron transfer

Area of Science:

• Microbiology
• Biogeochemistry
• Environmental Science

Background:

• Microbial communities utilize interspecies electron transfer (IET) for energy.
• Historically, IET relied on chemical intermediates like H2 or sulfur compounds.
• Direct interspecies electron transfer (DIET) represents an alternative mechanism.

Purpose of the Study:

• To review and highlight the mechanisms of interspecies electron transfer.
• To discuss the role of direct interspecies electron transfer (DIET) as an alternative to chemical intermediates.
• To emphasize the importance of IET in methanogenic communities.

Main Methods:

• Literature review of established and emerging IET mechanisms.
• Analysis of documented electrical contact strategies in DIET.
• Examination of IET's role in methane production.

Main Results:

• IET occurs via chemical intermediates (e.g., H2, sulfur) or direct electrical contact.
• DIET involves physical connections using conductive pili, minerals, or carbon materials.
• DIET is significant in some methanogenic communities where it can predominate over H2 transfer.

Conclusions:

• IET is fundamental to microbial community function, particularly in methanogenesis.
• DIET is a crucial, often overlooked, mode of microbial energy exchange.
• Further research is needed to understand environmental factors influencing IET strategies.