Abstract
Iron is a key element to understand global biogeochemical cycling. Microorganisms are involved in redox cycling of iron in natural environments. In particular, neutrophilic iron-oxidizing microorganisms that grow at circumneutral pH potentially play a significant role in global iron oxidation at redox boundaries. However, little is known about neutrophilic iron-oxidizing microorganisms because only a few cultivated species have been reported to date despite a long research history. In this review, knowledge about neutrophilic iron-oxidizing microorganisms, i.e., phylogeny, physiology, ecology, spatial distribution, and unique extracellular polymeric substances, is summarized, including the most recent reports. This will provide useful information to various scientific fields: not only microbiology, but also geochemistry, astrobiology and environmental engineering.
