Sulfurimonas is a bacterial genus within the class of Campylobacterota, known for reducing nitrate, oxidizing both sulfur and hydrogen, and containing Group IV hydrogenases. This genus consists of four species: Sulfurimonas autorophica, Sulfurimonas denitrificans, Sulfurimonas gotlandica, and Sulfurimonas paralvinellae. The genus' name is derived from "sulfur" in Latin and "monas" from Greek, together meaning a "sulfur-oxidizing rod". The size of the bacteria varies between about 1.5-2.5 μm in length and 0.5-1.0 μm in width. Members of the genus Sulfurimonas are found in a variety of different environments which include deep sea-vents, marine sediments, and terrestrial habitats. Their ability to survive in extreme conditions is attributed to multiple copies of one enzyme. Phylogenetic analysis suggests that members of the genus Sulfurimonas have limited dispersal ability and its speciation was affected by geographical isolation rather than hydrothermal composition. Deep ocean currents affect the dispersal of Sulfurimonas spp., influencing its speciation. As shown in the MLSA report of deep-sea hydrothermal vents Campylobacterota, Sulfurimonas has a higher dispersal capability compared with deep sea hydrothermal vent thermophiles, indicating allopatric speciation.
Characteristics
History of recognition "Auto" and 'trophicos" are derived from Greek words, where "auto" means self and 'trophicos" refers to nursing, tending or feeding, which indicates its autotrophy. The abundance and distribution of subgroups within the Campylobacterota and the genusSulfurimonas have been detected in the water column using a number of techniques including 16S rRNA cloning, catalyzed reporter deposition and fluorescence in situ hybridization (CARD-FISH), and quantitative PCR measurements. Water samples were collected at different depths and the concentrations of nutrients, oxygen, and sulfur measured immediately after sampling. The sample was measured for carbon fixation rate, and the DNA extracted and specific sequences amplified by PCR. The "denitrificans" portion in the name Sulfurimonas denitrificans (S. denitrificans) refers to its ability to reduce nitrate into di-nitrogen gas, a process known as denitrification. In 2006, Sulfurimonas denitrificans was the last species to be placed in the genus Sulfurimonas, as in 2000 it had been wrongly classified into the genus Thiomicrospira. Studies of Sulfurimonas gotlandica (S. gotlandica) have mostly been from the Baltic Sea, using transmission electron microscopy and fluorescence microscopy with phosphotungstic acid and DAPI stain as forms of visualization. Sulfurimonas paralvinellae was first obtained from a nest of deep-sea polychaete worms, particularly from the family Alvinellidae. Members from the genus Paralvinellae were found at a sulfide mound at a deep-sea hydrothermal vent in the Iheya North Field in the Mid-Okinawa Trough. The strain was initially separated from the nest via dilution-to-extinction technique. The strain was called GO25 T and had resembling physiological and phylogenetic characteristics of Sulfurimonas autotrophica. It was later determined that this species differs from Sulfurimonas autotrophica by having a distinct energy metabolism.
Phylogeny The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) and National Center for Biotechnology Information (NCBI).
Unassigned species:
"S. diazotrophicus" Zhong et al. 2025 "Ca. S. kebritensis" Alamoudi et al. 2025 "S. microaerophilus" Zhong et al. 2025
Metabolism Generally, bacteria have many pathways for metabolism, and in the case of members of the genus Sulfurimonas, this is how they are categorized into taxa. Members of the genus Sulfurimonas live in a wide range of environments, and play a vital role in chemoautotrophic processes, depending on the environment. Isolates of the four species in this genus have been shown to grow with a wide variety of electron acceptors and donors, allowing for members of the genus Sulfurimonas to grow in a wide variety of environments. Therefore, the success of Sulfurimonas spp. is credited to its ability to be a chemolithotroph, its flexible metabolism of changing electron acceptors/donors and sources of inorganic carbon, its oxygen tolerance and its ability to change with the environment. With differing environments, four types of energy metabolism are seen; including sulfur, hydrogen, nitrogen and carbon metabolism.
Sulfur metabolism As a sulfur-oxidizing Epsilonproteobacterium, studies have found that Sulfurimonas spp. use a wide variety of electron donors for growth including sulfide, sulfur, thiosulfate, and sulfite. However, as shown below, not all species can use each of the mentioned electron donors (Table 2). Multiple strains of the genus are capable of Microbial Sulfur Disproportionation (MSD) of elemental sulfur and thiosulfate. Sulfurimonas paralvinellae is able to use both molecular hydrogen and reduced sulfur for metabolism, which makes it only the second deep-sea Campylobacterota discovered to do so. Sulfurimonas paralvinellae is also capable of using yeast extract as a sulfur source. Molecular hydrogen is observed to yield a higher growth rate and is favored by Sulfurimonas paralvinellae over free reduced sulfur, even if the latter is present in the environment is excess. This can possibly be explained by the smaller amount of molecular hydrogen required to sustain growth in a bacterial cell as compared to reduced sulfur. Table 2. List of electron donors for Sulfurimonas species.
… excerpt ends here. Continue reading the full article.
