Anthony Ranchou-Peyruse

• Ph D
• Professor (Assistant) at Université de Pau et des Pays de l'Adour

In this review, selected examples are presented to demonstrate how microfluidic approaches can be utilized for investigating microbial life from deep geological environments, both from practical and fundamental perspectives. Beginning with the definition of the deep underground biosphere and the conventional experimental techniques employed for the...

Over the next few years, it is planned to convert all or part of the underground gas storage (UGS) facilities used for natural gas (salt caverns, depleted hydrocarbon reservoirs and deep aquifers) into underground hydrogen (H2) storage (UHS) reservoirs. These deep environments host microbial communities, some of which are hydrogenotrophic (sulfate...

If dihydrogen (H2) becomes a major part of the energy mix, massive storage in underground gas storage (UGS), such as in deep aquifers, will be needed. The development of H2 requires a growing share of H2 in natural gas (and its current infrastructure), which is expected to reach approximately 2% in Europe. The impact of H2 in aquifers is uncertain,...

The dihydrogen (H2) sector is undergoing development and will require massive storage solutions. To minimize costs, the conversion of underground geological storage sites, such as deep aquifers, used for natural gas storage into future underground hydrogen storage sites is the favored scenario. However, these sites contain microorganisms capable of...

Massive storage of dihydrogen (H2) in underground geological storage (UGSs) will be necessary to meet future H2 production ambitions. Such storage in deep aquifers was simulated in a high-pressure reactor, and the evolution of the 3 phases (natural gas/H2 , formation water and rock) with autochthonous microorganisms was monitored over several weeks...

Biomethane is considered one of the most promising energy vectors to substitute fossil fuels during the global energy transition. Its production is steadily increasing, and high storage volumes are needed to cover seasonal needs. Existing underground gas storage (UGS) aquifers, which have been used for natural gas storage, are excellent candidates....

L'hydrogène est une source d'énergie alternative de plus en plus étudiée. Il peut être naturellement émis sur les continents via des processus géochimiques comme la serpentinisation, mais aussi biologiques, via la production microbienne. La détection de ses zones d'émission est d'une grande importance pour comprendre ces mécanismes de production, m...

In response to the challenges of sustainable development and the H 2 sector, it is foreseeable that H 2 will be stored into geological storage, such as deep aquifers. However, CO 2 evolves in deep aquifers because it may be naturally present there; it may also be a constituent of the stored gas mix, or could even be voluntarily stored in the contex...

The Asal–Ghoubbet active rift in the Republic of Djibouti is a site of interest for geothermal energy and natural hydrogen, and previous studies have indicated that dihydrogen (H2) emanates from this rift. However, the well-known serpentinization reaction does not appear to be the main mechanism generating H2 at this site. Rather, the H2 is generat...

The Tiebaghi massif in New-Caledonia is composed of peridotites which are ultrabasic rocks that have been mined for nickel, cobalt and chromium. The peridotites can also be involved in the serpentinization, a natural dihydrogen (H2) and hydrocarbons production process. Microbial activities can interfere with these compounds and consume them for gro...

To be effective, microbiological studies of deep aquifers must be free from surface microbial contaminants and from infrastructures allowing access to formation water (wellheads, well completions). Many microbiological studies are based on water samples obtained after rinsing a well without guaranteeing the absence of contaminants from the biofilm...

This first multidisciplinary study simulating the H 2 arrival in deep aquifers used as geological storage shows the importance of microorganisms.

Deep aquifers (up to 2km deep) contain massive volumes of water harboring large and diverse microbial communities at high pressure. Aquifers are home to microbial ecosystems that participate in physicochemical balances. These microorganisms can positively or negatively interfere with subsurface (i) energy storage (CH4 and H2), (ii) CO2 sequestratio...

The last few years have seen the proliferation of anaerobic digestion plants to produce biomethane. Oxygen (O2) traces added to biogas during the desulfurization process are co-injected in the gas network and can be stored in Underground Gas Storage (UGS). However, there are no data available for the undesirable effects of O2 on these anoxic enviro...

Both molecular analyses and culture-dependent isolation were combined to investigate the diversity of sulfate-reducing prokaryotes and explore their role in sulfides production in full-scale anaerobic digesters (Marrakech, Morocco). At global scale, using 16S rRNA gene sequencing, Proteobacteria, Bacteroidetes, Firmicutes, Actinobacteria, Synergist...

BTEX (benzene, toluene, ethylbenzene, and the different xylene isomers), known for carcinogenic and neurotoxic effects, are common environmental contaminants. The first step for the development of the bioremediation technologies is the detection of intense microbial degradation in contaminated waters in the quest for the most active bacterial strai...

In this review, we present a general overview of the current progress in pore scale experimentations related to CO2 geological storage. In such processes occurring in porous media, most of the phenomena start from (bio)geochemical reactions and transport mechanisms at the pore scale. Therefore, in order to predict the overall consequences of CO2 in...

Mercury methylation converts inorganic mercury into the toxic methylmercury, and the consequences of this transformation are worrisome for human health and the environment. This process is performed by anaerobic microorganisms, such as several strains related to Pseudodesulfovibrio and Desulfovibrio genera. In order to provide new insights into the...

D'une apparente banalité et fragilité, les micro-capillaires de verre ont de fait des avantages cachés comme cellules pour l'étude de fluides complexes en conditions extrêmes. Faciles à charger par capillarité, bon marché, de section cylindrique, carrée, rectangulaire… allant du µm au mm, leur état de surface peut être contrôlé, e.g. par silanisati...

A novel anaerobic fermentative bacterium, strain SEBR 4209T, was isolated from a water sample of a Congolese oil field. Strain SEBR 4209T is phylogenetically related to the genus Pleomorphochaeta, in the family Spirochaetaceae. Its closest relatives are Pleomorphochaeta caudata SEBR 4223T (94.5 % 16S rRNA gene sequence similarity) and Pleomorphocha...

The strain BerOc1Twas isolated from brackish sediments contaminated with hydrocarbons and heavy metals. This strain has been used as a model strain of sulfate-reducer to study the biomethylation of mercury. The cells are vibrio-shaped, motile and not sporulated. Phylogeny and physiological traits placed this strain within the genus Pseudodesulfovib...

A novel, mesophilic, strictly anaerobic, sulfate-reducing and propionate-oxidizing bacterium, strain Prop6T, was enriched and isolated from a municipal anaerobic sewage sludge digester. Cells were Gram-negative, catalase-positive, oval rods, motile by means of amphitrichous flagella, non-spore-forming and contained menaquinone MK-5(H2) as the major...

A strictly anaerobic Gram-negative bacterium, designated strain SEBR 4223T, was isolated from the production water of an offshore Congolese oil field. Cells were non-motile, pleomorphic and having spherical, annular or budding shapes and often exhibiting long stalks. Strain SEBR 4223T grew on a range of carbohydrates, optimally at 37°C and pH 7, in...

Two novel strictly anaerobic bacteria, strains Bs105T and Bs107T, were isolated from a deep aquifer-derived hydrocarbonoclastic community. The cells were rod-shaped, not motile and had terminal spores. Phylogenetic affiliation and physiological properties revealed that these isolates belong to two novel species of the genus Desulfotomaculum . Optim...

Table S1. Primers and gene capture probes used in this study.

Table S2. Summary statistics from bssA gene capture coupled to Illumina sequencing.

The formation water of a deep aquifer (853 m of depth) used for geological storage of natural gas was sampled to assess the mono-aromatic hydrocarbons attenuation potential of the indigenous microbiota. The study of bacterial diversity suggests that Firmicutes and, in particular, sulphate-reducing bacteria (Peptococcaceae) predominate in this micro...

Deep subsurface aquifers despite difficult access, represent important water resources and, at the same time, are key locations for subsurface engineering activities for the oil and gas industries, geothermal energy, and CO2 or energy storage. Formation water originating from a 760 m-deep geological gas storage aquifer was sampled and microcosms we...

A novel, mesophilic, strictly anaerobic, sulfate-reducing and propionate-oxidizing bacterium, strain Prop6T, was enriched and isolated from a municipal anaerobic sewage sludge digester. Cells were Gram-negative, catalase-positive, oval rods, motile by means of amphitrichous flagella, non-spore-forming and contained menaquinone MK-5(H2) as the major...

Gram-positive spore-forming sulfate reducers and particularly members of the genus Desulfotomaculum are commonly found in the subsurface biosphere by culture based and molecular approaches. Due to their metabolic versatility and their ability to persist as endospores. Desulfotomaculum spp. are well-adapted for colonizing environments through a slow...

Strain VNs100T, a novel mesophilic anaerobic rod-cocoid-shaped bacterium, having a sheath-like outer structure (toga) was isolated from a water sample collected in the area of underground gas storage. It was non-motile with cells appearing singly (2-4 μm long x 1-2 μm wide), in pairs, or as long chains and stained Gram-negative. Strain VNs100T was...

Hydrogen-oxidising bacteria play a key ecological role in a variety of habitats including the rhizosphere and hot springs. To investigate the possibly of interspecies hydrogen exchange between cyanobacteria and hydrogen-oxidising bacteria, we developed a sensitive and reliable reverse-transcriptase qPCR assay for up-regulation of the hupS gene in t...

Knallgas bacteria are a physiologically defined group that is primarily studied using cultivation-dependent techniques. Given that current cultivation techniques fail to grow most bacteria, cultivation-independent techniques that selectively detect and identify knallgas bacteria will improve our ability to study their diversity and distribution. We...

Current knowledge of the pathways for the degradation of n-alkanes and n-alkenes by anaerobic bacteria is summarized and new results questioning the existence of an alternative pathway for anaerobic alkane degradation are introduced. Remaining gaps in our knowledge are also mentioned, together with the possible use of some specific metabolites as b...

The spatio-temporal distribution of sulfate-reducing bacteria (SRB) in the microbial mat of Camargue (Salins-de-Giraud, France) was investigated by molecular approaches at both microscale spatial resolution and different taxonomic organization levels. The vertical distribution of the SRB populations was correlated with oxygen and sulfide microgradi...

Current knowledge of the pathways for the degradation of n-alkaries and n-alkenes by anaerobic bacteria is summarized and new results questioning the existence of in alternative pathway For anacrobic alkane degradation are introduced. Remaining gaps in our knowledge are also mentioned, together with the possible Use of some specific metabolites its...

Hydrocarbonoclastic bacterial communities inhabiting mangrove sediments were characterized by combining molecular and culture-dependent approaches. Surface sediments were collected at two sampling sites in Guanabara Bay (Rio de Janeiro, Brazil) and used to inoculate in vitro enrichment cultures containing crude oil to obtain hydrocarbonoclastic bac...

Phototrophic anoxygenic purple bacteria play a key role in many aquatic ecosystems by oxidizing sulfur compounds and low-molecular-weight organic compounds using light as energy source. In this study, molecular methods based upon pufM gene (photosynthetic unit forming gene) were compared with culture-dependent methods to investigate anoxygenic purp...

The spatio-temporal distribution of phototrophic communities of the hypersaline photosynthetic Camarguc microbial mat (Salins-de-Giraud, France) was investigated over a diel cycle by combining microscopic and molecular approaches. Microcoleus chthonoplastes and Halomicronema excentricum, the dominant cyanobacteria of this oxyphotrophic community, w...

A dense 1 m thick layer of phototrophic purple sulfur bacteria is present at the pycnocline (17.8 m depth) in the meromictic South Andros Black Hole cave system (Bahamas). Two purple sulfur bacteria present in samples collected from this layer have been identified as belonging to the family Chromatiaceae. One isolate (BH-1), pink coloured, is non-m...

Anaerobic bacterial communities were selected by successive enrichments, under light conditions, on selected hydrocarbon molecules (aliphatic and aromatic). The original inocula came from an oil-contaminated microbial mat developing in a refinery waste water treatment plant in Berre Lagoon (Mediterranean Sea, France). Bacterial communities able to...