Merroun Mohamed

Merroun Mohamed
University of Granada | UGR · Department of Microbiology

About

136
Publications
22,391
Reads
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3,210
Citations
Citations since 2016
68 Research Items
1823 Citations
20162017201820192020202120220100200300
20162017201820192020202120220100200300
20162017201820192020202120220100200300
20162017201820192020202120220100200300
Additional affiliations
December 2008 - present
University of Granada
Position
  • Professor (Associate)

Publications

Publications (136)
Article
Uranium (U) roll-front deposits constitute a valuable source for an economical extraction by in situ recovery (ISR) mining. Such technology may induce changes in the subsurface microbiota, raising questions about the way their activities could build a functional ecosystem in such extreme environments (i.e.: oligotrophy and high SO4 concentration an...
Article
Nowadays, metal pollution due to the huge release of toxic elements to the environment has become one of the world's biggest problems. Bioremediation is a promising tool for reducing the mobility and toxicity of these contaminants (e.g. selenium), being an efficient, environmentally friendly, and inexpensive strategy. The present study describes th...
Article
Uranium contamination is a widespread problem caused by natural and anthropogenic activities. Although microorganisms thrive in uranium-contaminated environments, little is known about the actual molecular mechanisms mediating uranium resistance. Here, we investigated the resistance mechanisms driving the adaptation of Cupriavidus metallidurans NA4...
Article
Full-text available
Uranium (U) is the most hazardous radionuclide in nuclear waste and its harmful effects depend on its mobility and bioavailability. Microorganisms can affect the speciation of radionuclides and their migration in Deep Geological Repositories (DGR) for high level radioactive waste (HLW) storage. Consequently, a better understanding of microbe-radion...
Chapter
Biomineralization mediated by microorganisms is ubiquitous in nature. This process mostly encompasses phosphate, carbonate, silica and sulphate precipitation as well as iron mineralization. The mechanisms by which microbial biominerals are formed include intracellular and extracellular biomineralization. Minerals produced by microorganisms are ofte...
Article
Full-text available
The remediation of heavy-metal-contaminated sites represents a serious environmental problem worldwide. Currently, cost- and time-intensive chemical treatments are usually performed. Bioremediation by heavy-metal-tolerant microorganisms is considered a more eco-friendly and comparatively cheap alternative. The fungus Penicillium simplicissimum KS1,...
Article
Full-text available
Cyanobacterial carbonate precipitation induced by cyanobacterium Gloeocapsa enhances mortar durability. Cells are preferably attached to cement paste than sand grains and use atmospheric CO2 to precipitate carbonates. The cell coverage is higher in the presence of UV-killed cells than living cells, providing insights for microbial mortar restoratio...
Article
Full-text available
Uranium-containing effluents generated by nuclear energy industry must be efficiently remediated before release to the environment. Currently, numerous microbial-based strategies are being developed for this purpose. In particular, the bacterial strain Stenotrophomonas sp. Br8, isolated from U mill tailings porewaters, has been already shown to eff...
Preprint
Full-text available
Cyanobacterial carbonate precipitation induced by cells and extracellular polymeric substances (EPS) enhances mortar durability. The percentage of cell/EPS attachment regulates the effectiveness of the mortar restoration. This study investigates the cell coverage on mortar and microbially induced carbonate precipitation. Statistical analysis of res...
Article
Full-text available
Desulfovibrio desulfuricans reduces Pd(II) to Pd(0)-nanoparticles (Pd-NPs) which are catalytically active in 2-pentyne hydrogenation. To make Pd-NPs, resting cells are challenged with Pd(II) ions (uptake), followed by addition of electron donor to promote bioreduction of cell-bound Pd(II) to Pd(0) (bio-Pd). Application of radiofrequency (RF) radiat...
Article
Full-text available
Cupriavidus metallidurans is a model bacterium to study molecular metal resistance mechanisms and its use for the bioremediation of several metals has been shown. However, its mechanisms for radionuclide resistance are unexplored. We investigated the interaction with uranium and associated cellular response to uranium for Cupriavidus metallidurans...
Article
The widespread use of selenium (Se) in technological applications (e.g., solar cells and electronic devices) has led to an accumulation of this metalloid in the environment to toxic levels. The newly described bacterial strain Stenotrophomonas bentonitica BII-R7 has been demonstrated to reduce mobile Se(IV) to Se(0)-nanoparticles (Se(0)NPs) and vol...
Article
Full-text available
Bimetallic nanoparticle catalysts have attracted considerable attention due to their unique chemical and physical properties. The ability of metal-reducing bacteria to produce highly catalytically active monometallic nanoparticles is well known; however, the properties and catalytic activity of bimetallic nanoparticles synthesized with these organi...
Chapter
Clays are commonly used in design concepts for geological disposal of nuclear waste. It is thus essential to identify and quantify microbial communities in clay-rich samples to study microbial processes during geological disposal. Although advances in culture-independent techniques have enabled detailed studies of microbial communities in diverse e...
Chapter
Bentonites may be used as a buffer and backfill material in future deep geological repositories of high-level radioactive waste. These clay formations have been reported to host different metabolically active microorganisms with the potential to affect the biogeochemical cycles of carbon, phosphorus, and sulfur. Therefore, low porosity bentonites w...
Article
Full-text available
Radionuclides (RNs) generated by nuclear and civil industries are released in natural ecosystems and may have a hazardous impact on human health and the environment. RN-polluted environments harbour different microbial species that become highly tolerant of these elements through mechanisms including biosorption, biotransformation, biomineralizatio...
Article
Full-text available
Microbial communities occurring in reference materials for artificial barriers (e.g., bentonites) in future deep geological repositories of radioactive waste can influence the migration behavior of radionuclides such as curium (Cm III). This study investigates the molecular interactions between Cm III and its inactive analogue europium (Eu III) wit...
Article
Full-text available
Compacted bentonites are one of the best sealing and backfilling clays considered for use in Deep Geological Repositories of radioactive wastes. However, an in-depth understanding of their behavior after placement in the repository is required, including if the activity of indigenous microorganisms affects safety conditions. Here we provide an opti...
Article
Full-text available
The potential use of microorganisms in the bioremediation of U pollution has been extensively described. However, a lack of knowledge on molecular resistance mechanisms has become a challenge for the use of these technologies. We reported on the transcriptomic and microscopic response of Stenotrophomonas bentonitica BII-R7 exposed to 100 and 250 μM...
Article
Microbial bio-transformations of the essential trace element selenium are now recognized to occur among a wide variety of microorganisms. These transformations are used to convert this element into its assimilated form of selenocysteine, which is at the active center of a number of key enzymes, and to produce selenium nanoparticles, quantum dots, m...
Article
The environmental impact of uranium released during nuclear power production and related mining activity is an issue of great concern. Innovative environmental-friendly water remediation strategies, like those based on U biomineralization through phosphatase activity, are desirable. Here, we report the great U biomineralization potential of Stenotr...
Article
Full-text available
The deep geological repository (DGR) system is widely accepted as the solution for the disposal of radioactive wastes in the future. This concept is based on several natural and engineered barriers such as bentonite clays, which will encase the metal containers holding the radioactive waste. Microorganisms living therein can influence the mobility...
Article
Microbacterium are Gram-positive, nonspore-forming, rod-shaped bacteria inhabiting a wide range of environments including soil, water, dairy products, other living organisms, etc. Microbacterium sp. strain Be9, isolated from mill tailings porewaters in France, shows a remarkable behavior in presence of uranium under distinct conditions, which is th...
Article
A uranium-mineralized sandy aquifer, planned for mining by means of uranium in situ recovery (U ISR), harbors a reservoir of bacterial life that may influence the biogeochemical cycles surrounding uranium roll-front deposits. Since microorganisms play an important role at all stages of U ISR, a better knowledge of the resident bacteria before any I...
Preprint
Background Uranium-mineralized sandy aquifer, planned for a mining by in situ recovery (U ISR), harbors a reservoir of bacterial life that may influence the biogeochemical cycles surrounding the Uranium roll front deposits. Since microorganisms are likely to play an important role at all stages of U ISR, a better knowledge of the resident bacteria...
Article
The role of microbial processes in bioaccumulation of major and trace elements has been broadly demonstrated. However, microbial communities from marine sediments have been poorly investigated to this regard. In marine environments, particularly under high anthropogenic pressure, heavy metal accumulation increases constantly, which may lead to sign...
Article
Full-text available
The environmental conditions for the planned geological disposal of radioactive waste-including hyper-alkaline pH, radiation or anoxia-are expected to be extremely harsh for microbial activity. However, it is thought that microbial communities will develop in these repositories, and this would have implications for geodisposal integrity and the con...
Chapter
Following early reports, the literature now abounds with many examples of the use of biological materials to support, stabilise and incorporate metallic nanoparticles (NPs). This is noteworthy since precious metals (PMs) have no known biological functions. The use of biosupported PM metallic nanoparticles has been shown in green chemistry, remediat...
Article
Full-text available
Aerobic methane-oxidizing bacteria are ubiquitous in the environment. Two well-characterized strains, Mc . capsulatus (Bath) and Methylosinus trichosporium OB3b, representing gamma- and alphaproteobacterial methanotrophs, respectively, can convert selenite, an environmental pollutant, to volatile selenium compounds and selenium-containing particula...
Article
Understanding the impact of microorganisms on the mobility of selenium (Se) is important for predicting the fate of toxic Se in the environment and improving wastewater treatment technologies. The bacteria strain Bacillus safensis JG-B5T, isolated from soil in a uranium mining waste pile, can influence the Se speciation in the environment and engin...
Article
The multi-barrier deep geological repository system is currently considered as one of the safest option for the disposal of high-level radioactive wastes. Indigenous microorganisms of bentonites, may affect the structure and stability of these clays through Fe-containing minerals biotransformation and radionuclides mobilization. The present work ai...
Article
Full-text available
Escherichia coli cells support the nucleation and growth of ruthenium and ruthenium-palladium nanoparticles (Bio-Ru and Bio-Pd/Ru NPs). We report a method for the synthesis of these monometallic and bimetallic NPs and their application in the catalytic upgrading of 5-hydroxymethyl furfural (5-HMF) to 2,5 dimethylfuran (DMF). Examination using high...
Article
Full-text available
Numerous studies have focused on the bacterial synthesis of palladium nanoparticles (bio-Pd NPs), via uptake of Pd (II) ions and their enzymatically-mediated reduction to Pd (0). Cells of Desulfovibrio desulfuricans (obligate anaerobe) and Escherichia coli (facultative anaerobe, grown anaerobically) were exposed to low-dose radiofrequency (RF) radi...
Article
Full-text available
Biogas-energy is marginally profitable against the “parasitic” energy demands of processing biomass. Biogas involves microbial fermentation of feedstock hydrolyzate generated enzymatically or thermochemically. The latter also produces 5-hydroxymethyl furfural (5-HMF) which can be catalytically upgraded to 2, 5-dimethyl furan (DMF), a “drop in fuel....
Article
Full-text available
Bacillus benzeovorans assisted and supported growth of ruthenium (bio-Ru) and palladium/ruthenium (bio-Pd@Ru) core@shell nanoparticles (NPs) as bio-derived catalysts. Characterization of the bio-NPs using various electron microscopy techniques and high-angle annular dark field (HAADF) analysis confirmed two NP populations (1–2 nm and 5–8 nm), with...
Article
Full-text available
Remediation of former uranium mining sites represents one of the biggest challenges worldwide that have to be solved in this century. During the last years, the search of alternative strategies involving environmentally sustainable treatments has started. Bioremediation, the use of microorganisms to clean up polluted sites in the environment, is co...
Data
Colonies of KS5. Red colonies of KS5 appearing on solid SDA agar plates, incubation at 30°C for 48 hours. (TIF)
Data
STEM-EDXS analysis of an ultrathin-sectioned KS5 sample. After uranium removal experiments at 4°C for 48 h (a) HAADF-STEM micrograph together with EDX spectra (b) of a needle-like structure localized at the outer cytoplasm membrane. (TIF)
Article
Full-text available
Nuclear waste containing radionuclides including selenium isotopes, Se⁷⁹, will be disposed of in future deep geological repositories. Due to the long lifetime of these radioisotopes, studies on the impact of microbial processes on their chemical speciation would contribute significantly to understanding the risks associated with these repositories....
Conference Paper
Uranium mining is the first step in nuclear energy industry. This worldwide extended activity implies certain environmental risks which should be considered. In order to avoid detrimental impacts on nature, remediation approaches may be applied. Strategies based on microbial mechanisms are being increasingly studied in recent years. In particular,...
Article
Full-text available
This work describes the molecular characterization of the interaction mechanism of a bentonite yeast isolate, Rhodotorula mucilaginosa BII-R8, with curium(III) as representative of trivalent actinides and europium(III) used as inactive analogue of Cm(III). A multidisciplinary approach combining spectroscopy, microscopy and flow cytometry was applie...
Article
Full-text available
This study presents the effect of aqueous uranium speciation (U-hydroxides and U-hydroxo-carbonates) on the interaction of this radionuclide with the cells of the yeast Rhodotorula mucigilanosa BII-R8. This strain was isolated from Spanish bentonites considered as reference materials for the engineered barrier components of the future deep geologic...
Article
Full-text available
Deep geological repository (DGR) is one of the internationally accepted options to dispose radioactive wastes. Bentonite formations from Almeria, Spain, were selected as reference material for artificial barriers for the future Spanish repository. However, the safety of this long-term disposal could be compromised not only by physicochemical factor...
Article
Better understanding of uranyl-protein interactions is a prerequisite to predict uranium chemical toxicity in cells. The EF-hand motif of calmodulin site I is about thousand times more affine for uranyl than for calcium, and threonine phosphorylation increases uranyl affinity by two orders of magnitude at pH 7. In this study, we confront X-rays abs...
Article
Full-text available
A Gram-stain negative, rod-shaped, aerobic bacterial strain, BII-R7T, was isolated during a study targeting the culture-dependent microbial diversity occurring in bentonite formations from southern Spain. Comparative 16S rRNA gene sequence analysis showed that BII-R7T represented a member of the genus Stenotrophomonas (class Gammaproteobacteria), a...
Article
Full-text available
The Gram-negative bacterium Stenotrophomonas bentonitica BII-R7 T was isolated from bentonite formations. Like other species within the genus Stenotrophomonas , strain BII-R7 T possesses high tolerance to numerous heavy metals, suggesting potential for bioremediation purposes. The draft genome sequence reported here comprises 4.37 Mb with a G+C con...
Article
Full-text available
Dissimilatory reduction of sulfate, mediated by various species of sulfate-reducing bacteria (SRB) and a few characterized species of archaea, can be used to remediate acid mine drainage (AMD). Hydrogen sulfide (H2S/HS⁻) generated by SRB removes toxic metals from AMD as sulfide biominerals. For this, SRB are usually housed in separate reactor vesse...
Article
The present work describes lead phosphate biomineralization by a wood-decaying fungal isolate, Penicillium chrysogenum A15, after incubation in solid medium with metallic lead (Pb shot pellets). This fungal isolate showed high tolerance to this element, being able to grow on solid medium containing 8 mM Pb(II). Environmental Scanning Electron Micro...
Conference Paper
This paper describes the preparation and morphological and fine structural characteristics of biologically derived ruthenium and bimetallic palladium/ruthenium nanoparticles. Cells of E. coli strain MC400 were used for production of bio-supported Ru and Pd/Ru bimetallic nanoparticles (bio-Ru NPs and bio-Pd/Ru NPs). High-resolution scanning transmis...
Conference Paper
The main objective of the present work is to characterize the structure and size of selenium nanoparticles (Se NPs) produced by the bacterial strain Stenotrophomonas sp. BII-R7, using a combination of microbiological, spectroscopic and microscopic techniques. There are several microorganisms described for their ability to interact with selenium (Se...
Conference Paper
The present work consists in the isolation and characterization of bacterial strains from porewaters sampled in the vicinity of two French uranium tailing repositories. Since microbes are known to affect decisively uranium fate and behavior in these environments, their identification and characterization is considered the first logical step for the...
Article
We have developed a simple process to fabricate on a bioplatform patterns of nanoparticles of a molecule-based magnet. Nanoparticles of the ferromagnetic Prussian blue derivative CsxNi[Cr(CN)6] were orderly deposited onto S-layers of Lysinibacillus sphaericus, forming a dense carpet of nanoparticles following the square lattice (p4) pattern of the...