Rhodovulum sulfidophilum
[11] These draft genomes also revealed that they contained genes confirmed to be involved in cellular processes, such as carbon dioxide fixation and sulfur oxidation.
[11] A later study that analyzed isolates of R. sulfidophilum found that AB26 reserved around 16% of its entire 4,380,746 base pair genome to transport and also had 20 response regulators, and 22 histidine kinases.
[12] Another study that genetically characterized R. sulfidophilum discovered that the bacterium contained one copy of pucA and pucB (α- and β- genes) each within the puc operon.
[13] In addition, it was found that there were no Integration Host Factor (IHF) and Fumerate and Nitrate Reductase (FNR) regulation protein binding sites in this bacterial species like with Rhodobacter sphaeroides.
[15] Rhodovulum sulfidophilum is capable of oxidizing sulfide or thiosulfate to yield sulfates in the ecosystem without accumulating intermediates and have an unusual tri-heme cytochrome subunit bound to the reaction center, therefore allowing for photolithoautotrophic growth.
[1][16] Additionally, unlike other nonsulfur purple bacteria, R. sulfidophilum is able to synthesize its peripheral antenna complex under dark aerobic conditions.
[13] Multiple strains of R. sulfidophilum have also been shown to be capable of photoferrotrophy, a process that fixes inorganic carbon to organic material using light and Fe(II) as the electron donor.
[17][18] Rhodovulum sulfidophilum DSM 2351 is found to produce and excrete high levels of nucleic acids, which causes cell aggregates to form.
Rhodovulum sulfidophilum was originally isolated from the mud of the marine floor of the intertidal flats of the Dutch Waddenzee, north of the province of Groningen, Netherlands.
[21][22] Due to its metabolic flexibility, Rhodovulum sulfidophilum exhibits a relatively wide distribution and is found in a variety of aquatic habitats, especially anaerobic environments with high sulfide concentrations.
[23] While other Purple Non-Sulfur Bacteria (PNSB) species are incapable of surviving in sulfur-rich areas, these conditions are ideal for R.sulfidophilum as it utilizes sulfide as the donor for electrons when conducting photolithotrophic metabolic processes.
Much of the greenhouse gas produced by anthropogenic activities is stored within the ocean, which is the largest existing reservoir of carbon dioxide on earth.
[18] Considering that marine sediments account for about fifty percent of global primary production, it may be worthwhile looking into how photoferrotrophic organisms such as R. sulfidophilum could contribute to reducing the amount of excess carbon within the ocean.
[5] In 2020, a research team in Japan identified R. sulfidophilum as a sustainable and low cost silk producing microbial cell factory.
[30] Given that petroleum-derived plastics are expected to persist within the environment when discarded and therefore pose a threat as a widespread pollutant, continuous research is being conducted on the production bioplastic materials as a sustainable alternative.
[35] This bacterium does so via photo-fermentation which allows it to transform specific organic acids (OAs) such as succinate, lactate, and malate as single carbon sources into the following well known polymers of the PHA family, P3HB (poly-3-hydroxybutyrate) and P3HB-co-3 HV (3-hydroxybutyrateco-3-hydroxyvalerate).
Anoxygenic photosynthetic bacteria have been shown to produce higher amounts of PHA compared to oxygenic phototrophs, such as plants and cyanobacteria.
[36] As an anoxygenic sulfate reducing phototroph, R. sulfidophilum is used for bioremediation as it can grow in polluted environments, such as industrial fish processing wastewater.
[40] Kuruma shrimp (Marsupenaeus japonicus) is an important species in the global aquaculture industry, most notably being cultured in Japan and China.
After the addition of R. sulfidophilum various features of shrimp growth are improved: body weight (by 1.76-fold), survival rate (by 8.3%), and the feed conversion ratio (by 10%).
