Coupled C, H, N, S and Fe biogeochemical cycles operating in the continental deep subsurface of the Iberian Pyrite Belt.

Microbial activity is a major contributor to the biogeochemical cycles that make up the life support system of planet Earth. A 613 m deep geomicrobiological perforation and a systematic multi-analytical characterization revealed an unexpected diversity associated with the rock matrix microbiome that operates in the subsurface of the Iberian Pyrite Belt (IPB). Members of 1 class and 16 genera were deemed the most representative microorganisms of the IPB deep subsurface and selected for a deeper analysis. The use of fluorescence in situ hybridization allowed not only the identification of microorganisms but also the detection of novel activities in the subsurface such as anaerobic ammonium oxidation (ANAMMOX) and anaerobic methane oxidation, the co-occurrence of microorganisms able to maintain complementary metabolic activities and the existence of biofilms. The use of enrichment cultures sensed the presence of five different complementary metabolic activities along the length of the borehole and isolated 29 bacterial species. Genomic analysis of nine isolates identified the genes involved in the complete operation of the light-independent coupled C, H, N, S and Fe biogeochemical cycles. This study revealed the importance of nitrate reduction microorganisms in the oxidation of iron in the anoxic conditions existing in the subsurface of the IPB.

Biogeochemical Niches of Fe-Cycling Communities Influencing Heavy Metal Transport along the Rio Tinto, Spain.

In the mining-impacted Rio Tinto, Spain, Fe-cycling microorganisms influence the transport of heavy metals (HMs) into the Atlantic Ocean. However, it remains largely unknown how spatial and temporal hydrogeochemical gradients along the Rio Tinto shape the composition of Fe-cycling microbial communities and how this in turn affects HM mobility. Using a combination of DNA- and RNA-based 16S rRNA (gene) amplicon sequencing and hydrogeochemical analyses, we explored the impact of pH, Fe(III), Fe(II), and Cl- on Fe-cycling microorganisms. We showed that the water column at the acidic (pH 2.2) middle course of the river was colonized by Fe(II) oxidizers affiliated with Acidithiobacillus and Leptospirillum. At the upper estuary, daily fluctuations of pH (2.7 to 3.7) and Cl- (6.9 to 16.6 g/L) contributed to the establishment of a unique microbial community, including Fe(II) oxidizers belonging to Acidihalobacter, Marinobacter, and Mariprofundus, identified at this site. Furthermore, DNA- and RNA-based profiles of the benthic community suggested that acidophilic and neutrophilic Fe(II) oxidizers (e.g., Acidihalobacter, Marinobacter, and Mariprofundus), Fe(III) reducers (e.g., Thermoanaerobaculum), and sulfate-reducing bacteria drive the Fe cycle in the estuarine sediments. RNA-based relative abundances of Leptospirillum at the middle course as well as abundances of Acidihalobacter and Mariprofundus at the upper estuary were higher than DNA-based results, suggesting a potentially higher level of activity of these taxa. Based on our findings, we propose a model of how tidal water affects the composition and activity of the Fe-cycling taxa, playing an important role in the transport of HMs (e.g., As, Cd, Cr, and Pb) along the Rio Tinto. IMPORTANCE The estuary of the Rio Tinto is a unique environment in which extremely acidic, heavy metal-rich, and especially iron-rich river water is mixed with seawater. Due to the mixing events, the estuarine water is characterized by a low pH, almost seawater salinity, and high concentrations of bioavailable iron. The unusual hydrogeochemistry maintains unique microbial communities in the estuarine water and in the sediment. These communities include halotolerant iron-oxidizing microorganisms which typically inhabit acidic saline environments and marine iron-oxidizing microorganisms which, in contrast, are not typically found in acidic environments. Furthermore, highly saline estuarine water favored the prosperity of acidophilic heterotrophs, typically inhabiting brackish and saline environments. The Rio Tinto estuarine sediment harbors a diverse microbial community with both acidophilic and neutrophilic members that can mediate the iron cycle and, in turn, can directly impact the mobility and transport of heavy metals in the Rio Tinto estuary.

Sediminibacillus dalangtanensis sp. nov., a moderate halophile isolated from hypersaline sediments of the Qaidam Basin in Northwest China.

A Gram-stain-positive, moderately halophilic, aerobic, endospore-forming, rod-shaped bacterium, designated strain DP4-553-ST, was isolated from hypersaline sediment collected from the Dalangtan Playa in the Qaidam Basin, Northwest PR China. Growth occurred within 0-21.6% (w/v) NaCl (optimum 7.2%) at pH 5.5-9.0 (optimum pH 7.0) and at 4-45 °C (optimum 37 °C). Phylogeny based on 16S rRNA gene sequences indicated that strain DP4-553-ST belonged to the genus Sediminibacillus, with high 16S rRNA gene sequence similarity to Sediminibacillus halophilus EN8dT (99.5 %), Sediminibacillus terrae JSM 102062T (99.4 %), Virgibacillus senegalensis SK-1T (99.3 %) and Sediminibacillus albus NHBX5T (98.3 %). The G+C content of the chromosomal DNA was 43.6 mol %. The average amino acid identity, average nucleotide identity and digital DNA-DNA hybridization values between strain DP4-553-ST and the four close type strains were 71.2-93.3, 74.0-90.5 and 20.0-41.4 %, respectively. The whole genomic analysis showed that strain DP4-553-ST constituted a different taxon separated from the recognized Sediminibacillus species. The major cellular fatty acids were anteiso-C15 : 0, anteiso-C17 : 0, iso-C16 : 0, C16 : 0 and iso-C15 : 0. The type strain contained cell-wall peptidoglycan based on diaminopimelic acid and possessed menaquinone-7 as the major respiratory isoprenoid quinone. The polar lipid pattern consisted of diphosphatidylglycerol, phosphatidylglycerol, four unidentified glycolipids, phosphatidylcholine, aminophospholipid, aminolipid and seven unidentified phospholipids. The combined data from phenotypic and genotypic studies demonstrated that strain DP4-553-ST represents a novel species of the genus Sediminibacillus, for which the name Sediminibacillus dalangtanensis sp. nov. is proposed, the type strain is DP4-553-ST (=MCCC 1K03838T= KCTC 43250T).

Biological production of H2 , CH4 and CO2 in the deep subsurface of the Iberian Pyrite Belt.

Most of the terrestrial deep subsurfaces are oligotrophic environments in which some gases, mainly H2 , CH4 and CO2 , play an important role as energy and/or carbon sources. In this work, we assessed their biotic and abiotic origin in samples from subsurface hard-rock cores of the Iberian Pyrite Belt (IPB) at three different depths (414, 497 and 520 m). One set of samples was sterilized (abiotic control) and all samples were incubated under anaerobic conditions. Our results showed that H2 , CH4 and CO2 remained low and constant in the sterilized controls while their levels were 4, 4.1 and 2.5 times higher respectively, in the unsterilized samples compared to the abiotic controls. The δ13 CCH4 -values measured in the samples (range -31.2 to -43.0 ‰) reveals carbon isotopic signatures that are within the range for biological methane production. Possible microorganisms responsible for the biotic production of the gases were assessed by CARD-FISH. The analysis of sequenced genomes of detected microorganisms within the subsurface of the IPB allowed to identify possible metabolic activities involved in H2 (Rhodoplanes, Shewanella and Desulfosporosinus), CH4 (Methanobacteriales) and CO2 production. The obtained results suggest that part of the H2 , CH4 and CO2 detected in the deep subsurface has a biological origin.

Subsurface and surface halophile communities of the chaotropic Salar de Uyuni.

Salar de Uyuni (SdU) is the biggest athalosaline environment on Earth, holding a high percentage of the known world Li reserves. Due to its hypersalinity, temperature and humidity fluctuations, high exposure to UV radiation, and its elevated concentration of chaotropic agents like MgCl2 , LiCl and NaBr, SdU is considered a polyextreme environment. Here, we report the prokaryotic abundance and diversity of 46 samples obtained in different seasons and geographical areas. The identified bacterial community was found to be more heterogeneous than the archaeal community, with both communities varying geographically. A seasonal difference has been detected for archaea. Salinibacter, Halonotius and Halorubrum were the most abundant genera in Salar de Uyuni. Different unclassified archaea were also detected. In addition, the diversity of two subsurface samples obtained at 20 and 80 m depth was evaluated and compared with the surface data, generating an evolutionary record of a multilayer hypersaline ecosystem.

Astrobiology of life on Earth.

Astrobiology is mistakenly regarded by some as a field confined to studies of life beyond Earth. Here, we consider life on Earth through an astrobiological lens. Whereas classical studies of microbiology historically focused on various anthropocentric sub-fields (such as fermented foods or commensals and pathogens of crop plants, livestock and humans), addressing key biological questions via astrobiological approaches can further our understanding of all life on Earth. We highlight potential implications of this approach through the articles in this Environmental Microbiology special issue 'Ecophysiology of Extremophiles'. They report on the microbiology of places/processes including low-temperature environments and chemically diverse saline- and hypersaline habitats; aspects of sulphur metabolism in hypersaline lakes, dysoxic marine waters, and thermal acidic springs; biology of extremophile viruses; the survival of terrestrial extremophiles on the surface of Mars; biological soils crusts and rock-associated microbes of deserts; subsurface and deep biosphere, including a salticle formed within Triassic halite; and interactions of microbes with igneous and sedimentary rocks. These studies, some of which we highlight here, contribute to our understanding of the spatiotemporal reach of Earth'sfunctional biosphere, and the tenacity of terrestrial life. Their findings will help set the stage for future work focused on the constraints for life, and how organisms adapt and evolve to circumvent these constraints.

Viable cyanobacteria in the deep continental subsurface.

Cyanobacteria are ecologically versatile microorganisms inhabiting most environments, ranging from marine systems to arid deserts. Although they possess several pathways for light-independent energy generation, until now their ecological range appeared to be restricted to environments with at least occasional exposure to sunlight. Here we present molecular, microscopic, and metagenomic evidence that cyanobacteria predominate in deep subsurface rock samples from the Iberian Pyrite Belt Mars analog (southwestern Spain). Metagenomics showed the potential for a hydrogen-based lithoautotrophic cyanobacterial metabolism. Collectively, our results suggest that they may play an important role as primary producers within the deep-Earth biosphere. Our description of this previously unknown ecological niche for cyanobacteria paves the way for models on their origin and evolution, as well as on their potential presence in current or primitive biospheres in other planetary bodies, and on the extant, primitive, and putative extraterrestrial biospheres.

Impact of Simulated Martian Conditions on (Facultatively) Anaerobic Bacterial Strains from Different Mars Analogue Sites.

Five bacterial (facultatively) anaerobic strains, namely Buttiauxella sp. MASE-IM-9, Clostridium sp. MASE-IM-4, Halanaerobium sp. MASE-BB-1, Trichococcus sp. MASE-IM-5, and Yersinia intermedia MASE-LG-1 isolated from different extreme natural environments were subjected to Mars relevant environmental stress factors in the laboratory under controlled conditions. These stress factors encompassed low water activity, oxidizing compounds, and ionizing radiation. Stress tests were performed under permanently anoxic conditions. The survival rate after addition of sodium perchlorate (Na-perchlorate) was found to be species-specific. The inter-comparison of the five microorganisms revealed that Clostridium sp. MASE-IM-4 was the most sensitive strain (D10-value (15 min, NaClO4) = 0.6 M). The most tolerant microorganism was Trichococcus sp. MASE-IM-5 with a calculated D10-value (15 min, NaClO4) of 1.9 M. Cultivation in the presence of Na-perchlorate in Martian relevant concentrations up to 1 wt% led to the observation of chains of cells in all strains. Exposure to Na-perchlorate led to a lowering of the survival rate after desiccation. Consecutive exposure to desiccating conditions and ionizing radiation led to additive effects. Moreover, in a desiccated state, an enhanced radiation tolerance could be observed for the strains Clostridium sp. MASE-IM-4 and Trichococcus sp. MASE-IM-5. These data show that anaerobic microorganisms from Mars analogue environments can resist a variety of Martian-simulated stresses either individually or in combination. However, responses were species-specific and some Mars-simulated extremes killed certain organisms. Thus, although Martian stresses would be expected to act differentially on microorganisms, none of the expected extremes tested here and found on Mars prevent the growth of anaerobic microorganisms.

Prokaryotic and viral community structure in the singular chaotropic salt lake Salar de Uyuni.

Salar de Uyuni (SdU) is the largest hypersaline salt flat and the highest lithium reservoir on Earth. In addition to extreme temperatures and high UV irradiance, SdU has high concentrations of chaotropic salts which can be important factors in controlling microbial diversity. Here, for the first time we characterize the viral diversity of this hypersaline environment during the two seasons, as well as the physicochemical characteristics and the prokaryotic communities of the analysed samples. Most of the selected samples showed a peculiar physicochemical composition and prokaryotic diversity, mostly different from each other even for samples from locations in close proximity or the same season. In contrast to most hypersaline systems Bacteria frequently outnumbered Archaea. Furthermore, an outstanding percentage of members of Salinibacter sp., likely a species different from the cosmopolitan Salinibacter ruber, was obtained in most of the samples. Viral communities displayed the morphologies normally found in hypersaline environments. Two seasonal samples were chosen for a detailed metagenomic analysis of the viral assemblage. Both viral communities shared common sequences but were dominated by sample-specific viruses, mirroring the differences also observed in physicochemical and prokaryotic community composition. These metaviromes were distinct from those detected in other hypersaline systems analysed to date.

Adaptation of granular sludge microbial communities to nitrate, sulfide, and/or p-cresol removal.

Effluents from petroleum refineries contain a toxic mixture of sulfide, nitrogen, and phenolic compounds that require adequate treatment for their removal. Biological denitrification processes are a cost-effective option for the treatment of these effluents, but the knowledge on the microbial interactions in simultaneous sulfide and phenol oxidation in denitrifying reactors is still very limited. In this work, microbial community structure and macrostructure of granular biomass were studied in three denitrifying reactors treating a mixture of inorganic (sulfide) and organic (p-cresol) electron donors for their simultaneous removal. The differences in the available substrates resulted in different community assemblies that supported high removal efficiencies, indicating the community adaptation capacity to the fluctuating compositions of industrial effluents. The three reactors were dominated by nitrate reducing and denitrifying bacteria where Thiobacillus spp. were the prevalent denitrifying organisms. The toxicity and lack of adequate substrates caused the endogenous decay of the biomass, leading to release of organic matter that maintained a diverse although not very abundant group of heterotrophs. The endogenous digestion of the granules caused the degradation of its macrostructure, which should be considered to further develop the denitrification process in sulfur-based granular reactors for treatment of industrial wastewater with toxic compounds.

Microbial diversity associated with the anaerobic sediments of a soda lake (Mono Lake, California, USA).

Soda lakes are inhabited by important haloalkaliphilic microbial communities that are well adapted to these extreme characteristics. The surface waters of the haloalkaline Mono Lake (California, USA) are alkaline but, in contrast to its bottom waters, do not present high salinity. We have studied the microbiota present in the shoreline sediments of Mono Lake using next-generation sequencing techniques. The statistical indexes showed that Bacteria had a higher richness, diversity, and evenness than Archaea. Seventeen phyla and 8 "candidate divisions" were identified among the Bacteria, with a predominance of the phyla Firmicutes, Proteobacteria, and Bacteroidetes. Among the Proteobacteria, there was a notable presence of Rhodoplanes and a high diversity of sulfate-reducing Deltaproteobacteria, in accordance with the high sulfate-reducing activity detected in soda lakes. Numerous families of bacterial fermenters were identified among the Firmicutes. The Bacteroides were represented by several environmental groups that have not yet been isolated. Since final organic matter in anaerobic environments with high sulfate contents is mineralized mainly by sulfate-reducing bacteria, very little methanogenic archaeal biodiversity was detected. Only 2 genera, Methanocalculus and Methanosarcina, were retrieved. The species similarities described indicate that a significant number of the operational taxonomic units identified may represent new species.

Prokaryotic diversity and community composition in the Salar de Uyuni, a large scale, chaotropic salt flat.

Salar de Uyuni (SdU), with a geological history that reflects 50 000 years of climate change, is the largest hypersaline salt flat on Earth and is estimated to be the biggest lithium reservoir in the world. Its salinity reaches saturation levels for NaCl, a kosmotropic salt, and high concentrations of MgCL2 and LiCl, both salts considered important chaotrophic stressors. In addition, extreme temperatures, anoxic conditions, high UV irradiance, high albedo and extremely low concentrations of phosphorous, make SdU a unique natural extreme environment in which to contrast hypotheses about limiting factors of life diversification. Geophysical studies of brines from different sampling stations show that water activity is rather constant along SdU. Geochemical measurements show significant differences in magnesium concentration, ranging from 0.2 to 2M. This work analyses the prokaryotic diversity and community structure at four SdU sampling stations, selected according to their location and ionic composition. Prokaryotic communities were composed of both Archaea (with members of the classes Halobacteria, Thermoplasmata and Nanohaloarchaea, from the Euryarchaeota and Nanohaloarcheota phyla respectively) and Bacteria (mainly belonging to Bacteroidetes and Proteobacteria phyla). The important differences in composition of microbial communities inversely correlate with Mg2+ concentration, suggesting that prokaryotic diversity at SdU is chaotropic dependent.

Stability against freezing of aqueous solutions on early Mars.

Many features of the Martian landscape are thought to have been formed by liquid water flow and water-related mineralogies on the surface of Mars are widespread and abundant. Several lines of evidence, however, suggest that Mars has been cold with mean global temperatures well below the freezing point of pure water. Martian climate modellers considering a combination of greenhouse gases at a range of partial pressures find it challenging to simulate global mean Martian surface temperatures above 273 K, and local thermal sources cannot account for the widespread distribution of hydrated and evaporitic minerals throughout the Martian landscape. Solutes could depress the melting point of water in a frozen Martian environment, providing a plausible solution to the early Mars climate paradox. Here we model the freezing and evaporation processes of Martian fluids with a composition resulting from the weathering of basalts, as reflected in the chemical compositions at Mars landing sites. Our results show that a significant fraction of weathering fluids loaded with Si, Fe, S, Mg, Ca, Cl, Na, K and Al remain in the liquid state at temperatures well below 273 K. We tested our model by analysing the mineralogies yielded by the evolution of the solutions: the resulting mineral assemblages are analogous to those actually identified on the Martian surface. This stability against freezing of Martian fluids can explain saline liquid water activity on the surface of Mars at mean global temperatures well below 273 K.

Tessaracoccus lapidicaptus sp. nov., an actinobacterium isolated from the deep subsurface of the Iberian pyrite belt.

A novel actinobacterium, designated IPBSL-7(T), was isolated from a drilling core 297 m deep obtained from the Iberian Pyrite Belt. The strain was isolated anaerobically using nitrate as the electron acceptor. 16S rRNA gene sequence analysis revealed that it was related to Tessaracoccus flavescens SST-39(T) (95.7% similarity), Tessaracoccus bendigoensis Ben 106(T) (95.7%), Tessaracoccus lubricantis KSS-17Se(T) (95.6%) and Tessaracoccus oleiagri SL014B-20A1(T) (95.0%), while its similarity to any other member of the family Propionibacteriaceae was less than 94%. Cells were non-motile, non-spore-forming, Gram-positive, oval to rod-shaped, and often appeared in pairs or small groups. The strain was facultatively anaerobic, oxidase-negative, catalase-positive and capable of reducing nitrate. Colonies were circular, convex, smooth and colourless. The organism could grow at between 15 and 40 °C, with an optimal growth at 37 °C. The pH range for growth was from pH 6 to 9, with pH 8 being the optimal value. Strain IPBSL-7(T) had peptidoglycan type A3-γ', with ll-diaminopimelic acid as the diagnostic diamino-acid and glycine at position 1 of the peptide subunit. The dominant menaquinone was MK-9(H4) (93.8%). The major cellular fatty acid was anteiso-C15:0 (55.0%). The DNA G+C content was 70.3 mol%. On the basis of phenotypic and phylogenetic results, strain IPBSL-7(T) can be differentiated from previously described species of the genus Tessaracoccus and, therefore, represents a novel species, for which the name Tessaracoccus lapidicaptus sp. nov. is proposed. The type strain is IPBSL-7(T) ( = CECT 8385(T) = DSM 27266(T)).

Association of Acidotolerant Cyanobacteria to Microbial Mats below pH 1 in Acidic Mineral Precipitates in Río Tinto River in Spain.

This report describes acidic microbial mats containing cyanobacteria that are strongly associated to precipitated minerals in the source area of Río Tinto. Río Tinto (Huelva, Southwestern Spain) is an extreme acidic environment where iron and sulfur cycles play a fundamental role in sustaining the extremely low pH and the high concentration of heavy metals, while maintaining a high level of microbial diversity. These multi-layered mineral deposits are stable all year round and are characterized by a succession of thick greenish-blue and brownish layers mainly composed of natrojarosite. The temperature and absorbance above and below the mineral precipitates were followed and stable conditions were detected inside the mineral precipitates. Different methodologies, scanning and transmission electron microscopy, immunological detection, fluorescence in situ hybridization, and metagenomic analysis were used to describe the biodiversity existing in these microbial mats, demonstrating, for the first time, the existence of acid-tolerant cyanobacteria in a hyperacidic environment of below pH 1. Up to 0.46% of the classified sequences belong to cyanobacterial microorganisms, and 1.47% of the aligned DNA reads belong to the Cyanobacteria clade.

Physicochemical characterization of Acidiphilium sp. biofilms.

The biofilm formation of a strain of the extremophile bacterium Acidiphilium sp., capable of donating electrons directly to electrodes, was studied by different surface characterization techniques. We develop a method that allows the simultaneous study of bacterial biofilms by means of fluorescence microscopy and atomic force microscopy (AFM), in which transparent graphitic flakes deposited on a glass substrate are used as a support for the biofilm. The majority of the cells present on the surface were viable, and the growth of the biofilms over time showed a critical increase of the extracellular polymeric substances (EPS) as well as the formation of nanosized particles inside the biofilm. Also, the presence of Fe in Acidiphilium biofilms was determined by X-ray photoelectron spectroscopy (XPS), whereas surface-enhanced infrared absorption spectroscopy indicated the presence of redox-active proteins.

Noachian and more recent phyllosilicates in impact craters on Mars.

Hundreds of impact craters on Mars contain diverse phyllosilicates, interpreted as excavation products of preexisting subsurface deposits following impact and crater formation. This has been used to argue that the conditions conducive to phyllosilicate synthesis, which require the presence of abundant and long-lasting liquid water, were only met early in the history of the planet, during the Noachian period (> 3.6 Gy ago), and that aqueous environments were widespread then. Here we test this hypothesis by examining the excavation process of hydrated minerals by impact events on Mars and analyzing the stability of phyllosilicates against the impact-induced thermal shock. To do so, we first compare the infrared spectra of thermally altered phyllosilicates with those of hydrated minerals known to occur in craters on Mars and then analyze the postshock temperatures reached during impact crater excavation. Our results show that phyllosilicates can resist the postshock temperatures almost everywhere in the crater, except under particular conditions in a central area in and near the point of impact. We conclude that most phyllosilicates detected inside impact craters on Mars are consistent with excavated preexisting sediments, supporting the hypothesis of a primeval and long-lasting global aqueous environment. When our analyses are applied to specific impact craters on Mars, we are able to identify both pre- and postimpact phyllosilicates, therefore extending the time of local phyllosilicate synthesis to post-Noachian times.

Vitamin B12 Auxotrophy in Isolates from the Deep Subsurface of the Iberian Pyrite Belt.

Vitamin B12 is an enzymatic cofactor that is essential for both eukaryotes and prokaryotes. The development of life in extreme environments depends on cofactors such as vitamin B12 as well. The genomes of twelve microorganisms isolated from the deep subsurface of the Iberian Pyrite Belt have been analyzed in search of enzymatic activities that require vitamin B12 or are involved in its synthesis and import. Results have revealed that vitamin B12 is needed by these microorganisms for several essential enzymes such as ribonucleotide reductase, methionine synthase and epoxyqueosine reductase. Isolate Desulfosporosinus sp. DEEP is the only analyzed genome that holds a set core of proteins that could lead to the production of vitamin B12. The rest are dependent on obtaining it from the subsurface oligotrophic environment in which they grow. Sought proteins involved in the import of vitamin B12 are not widespread in the sample. The dependence found in the genomes of these microorganisms is supported by the production of vitamin B12 by microorganisms such as Desulfosporosinus sp. DEEP, showing that the operation of deep subsurface biogeochemical cycles is dependent on cofactors such as vitamin B12.

Production and Characterisation of an Exopolysaccharide by Bacillus amyloliquefaciens: Biotechnological Applications.

The Bacillus amyloliquefaciens RT7 strain was isolated from an extreme acidic environment and identified. The biodegradation capabilities of the strain using different carbon sources (glucose, oleic acid, Tween 80, PEG 200, and the combination of glucose-Tween 80) were evaluated via an indirect impedance technique. The glucose-Tween 80 combination was further studied using nuclear magnetic resonance (NMR). The exopolysaccharide (EPSRT7) that had been produced with the strain when biodegrading glucose-Tween 80 was isolated and characterised using different techniques (GC-MS, HPLC/MSMS, ATR-FTIR, TGA, and DSC), and its molecular weight was estimated. The results show that the average molecular weight of EPSRT7 was approximately 7.0794 × 104 Da and a heteropolysaccharide composed of mannose, glucose, galactose, and xylose (molar ratio, 1:0.5:0.1:0.1) with good thermostability. EPSRT7 showed good emulsifying activity against different natural oils and hydrocarbons at high concentrations (2 mg/mL) and at the studied pH range (3.1-7.2). It also presented good emulsifying activity compared to that of commercial emulsifiers. Lastly, EPSRT7 showed antioxidant capacity for different free radicals, a lack of cytotoxicity, and antioxidant activity at the cellular level. EPSRT7 has promising applications in bioremediation processes and other industrial applications.