Metabolism of One-Carbon Compounds by Chemotrophic Anaerobes

Abstract

Publisher Summary This chapter focuses on the metabolism of one-carbon (C1) compounds chemotrophic anaerobes. C1-metabolizing species possess novel physiologies that are distinctive in many ways from the autotrophic and heterotrophic microorganisms, which seemingly are more widespread in the microbial world. C1 compounds refer to any oxidizable one-carbon substrate that contains carbon-bound electrons. A C1 substrate differs noticeably from the C1 compound carbon dioxide because, in addition to being able to be reduced or assimilated, it can also be oxidized and can provide electrons for use in energy metabolism or cell synthesis. The term “chemotrophic anaerobe” refers to any obligately non-oxygen-catabolizing microbial species whose growth is solely dependent on the generation of metabolic energy from chemical substrates. The chapter examines the microbial physiology that accounts for unicarbonotrophy in anaerobes. The C1 metabolites enter anaerobic ecosystems of the biosphere either as pollutants from aerobic environments, volcanic or deep subsurface emanations, or via chemical transformation reactions performed by anaerobic microorganisms. The formation of C1 metabolites often necessitates their removal in biological elemental cycles because they can accumulate and alters normal carbon and electron flow within a cell, or becomes toxic and result in cell death.