Clostridium peptidivorans is an anaerobic, endospore-forming bacterium in the family Clostridiaceae specialized in the fermentation of peptides and amino acids, as indicated by the species epithet meaning 'peptide-devouring.' It was isolated from anaerobic environments rich in proteinaceous material, including oil field brine waters and sediments where complex organic nitrogen compounds are abundant. Like all clostridia, it is a strictly anaerobic, Gram-positive, rod-shaped bacterium that forms resistant endospores. C. peptidivorans uses Stickland fermentation reactions — coupled oxidation and reduction of amino acid pairs — to derive energy from peptide and amino acid substrates, producing organic acids, ammonia, and other end products. The ability to metabolize peptides makes it an active participant in the anaerobic degradation of protein-rich organic matter in subsurface environments. Its discovery in oil field environments suggests that peptidivoranous clostridia play roles in the anaerobic cycling of organic nitrogen in deep subsurface biotopes, contributing to biogeochemical processes in petroleum-associated anaerobic microbial communities.