Florin Musat

• PhD
• Associate Professor at Aarhus University

The introduction of antibiotic-resistant bacteria into riverine systems through the discharge of wastewater treatment plant (WWTP) effluent and agricultural waste poses significant health risks. Even when not pathogenic, these bacteria can act as reservoirs for antibiotic resistance genes (ARGs), transferring them to pathogens that infect humans an...

Microbial formation and oxidation of volatile alkanes in anoxic environments significantly impacts biogeochemical cycles on Earth. The discovery of archaea oxidizing volatile alkanes via deeply branching methyl-coenzyme M reductase variants, dubbed alkyl-CoM reductases (ACR), prompted the hypothesis of archaea-catalysed alkane formation in nature (...

Polycyclic aromatic hydrocarbon (PAH) contamination in marine environments range from low-diffusive inputs to high loads. The influence of PAH concentration on the expression of functional genes (e.g., those encoding ring-hydroxylating dioxygenases; RHDs), has been overlooked in PAH biodegradation studies. However, understanding marker-gene express...

Anaerobic microbial corrosion of iron‐containing metals causes extensive economic damage. Some microbes are capable of direct metal‐to‐microbe electron transfer (electrobiocorrosion), but the prevalence of electrobiocorrosion among diverse methanogens and acetogens is poorly understood because of a lack of tools for their genetic manipulation. Prev...

Ductile cast iron is a candidate material for long term nuclear waste repository canisters. However, little is known about microbial corrosion of this material, a phenomenon threatening the integrity of the repository. Here, the corrosion of ductile cast iron (92.73%–94.19% Fe) and mild steel (∼99.37% Fe) by the sulphate reducing bacterium Desulfop...

Multi element compound-specific stable isotope analysis (ME-CSIA) is a tool to assess (bio)chemical reactions of molecules in the environment based on their isotopic fingerprints. To that effect, ME-CSIA concepts are initially developed with laboratory model experiments to determine the isotope fractionation factors specific for distinct (bio)chemi...

Anaerobic microbial corrosion of iron-containing metals causes extensive economic damage. Some microbes are capable of direct metal-to-microbe electron transfer (electrobiocorrosion), but the prevalence of electrobiocorrosion among diverse methanogens and acetogens is poorly understood because of a lack of tools for their genetic manipulation. Prev...

[This corrects the article DOI: 10.3389/fmicb.2023.1058350.].

Introduction Currently there are sparse regulations regarding the discharge of antibiotics from wastewater treatment plants (WWTP) into river systems, making surface waters a latent reservoir for antibiotics and antibiotic resistance genes (ARGs). To better understand factors that influence the fate of ARGs in the environment and to foster surveill...

Microbial interactions impact the functioning of both natural and engineered systems, yet our ability to directly monitor these highly dynamic and spatially resolved interactions in living cells is very limited. Here, we developed a synergistic approach coupling single-cell Raman microspectroscopy with 15N2 and 13CO2 stable isotope probing in a mic...

The metabolic potential of the sulfate‐reducing bacterium Desulfosarcina sp. strain BuS5, currently the only pure culture able to oxidize the volatile alkanes propane and butane without oxygen, was investigated via genomics, proteomics and physiology assays. Complete genome sequencing revealed that strain BuS5 encodes a single alkyl‐succinate synth...

Microbial populations often display different degrees of heterogeneity in their substrate assimilation, that is, anabolic heterogeneity. It has been shown that nutrient limitations are a relevant trigger for this behavior. Here we explore the dynamics of anabolic heterogeneity under nutrient replete conditions. We applied time‐resolved stable isoto...

Carbon and hydrogen stable isotope effects associated with methane formation by the corrosive archaeon Methanobacterium strain IM1 were determined during growth with hydrogen and iron. Isotope analyses were complemented by structural, elemental and molecular composition analyses of corrosion crusts. During growth with H2 , strain IM1 formed methane...

Most microorganisms in the biosphere remain uncultured and poorly characterized. Although the surge in genome sequences has enabled insights into the genetic and metabolic properties of uncultured microorganisms, their physiology and ecological roles cannot be determined without direct probing of their activities in natural habitats. Here we employ...

Favorable interspecies associations prevail in natural microbial assemblages. Some of these favorable associations are co-metabolic dependent partnerships in which extracellular electrons are exchanged between species. For such electron exchange to occur, the cells must exhibit electroactive interfaces and get involved in direct cell-to-cell contac...

The aromatic hydrocarbon naphthalene, which occurs in coal and oil, can be degraded by aerobic or anaerobic microorganisms. A wide‐spread electron acceptor for the latter is sulfate. Evidence for in situ naphthalene degradation stems in particular from the detection of 2‐naphthoate and [5,6,7,8]‐tetrahydro‐2‐naphthoate in oil field samples. Because...

The rise of oxygen on the early Earth about 2.4 billion years ago reorganized the redox cycle of harmful metal(loids), including that of arsenic, which doubtlessly imposed substantial barriers to the physiology and diversification of life. Evaluating the adaptive biological responses to these environmental challenges is inherently difficult because...

Phenotypic heterogeneity within microbial populations arises even when the cells are exposed to putatively constant and homogeneous conditions. The outcome of this phenomenon can affect the whole function of the population, resulting in, for example, new “adapted” metabolic strategies and impacting its fitness at given environmental conditions. Acc...

The interdisciplinary project iCROSS combines research competencies of five Helmholtz Centers in the topics of radiochemistry, geosciences, biosciences, geotechnical engineering and computational sciences, to contribute to the safe disposal of radioactive waste. Specifically, research concentrates to those host rock formations where the repository...

Ethane is the second most abundant component of natural gas in addition to methane, and—similar to methane—is chemically unreactive. The biological consumption of ethane under anoxic conditions was suggested by geochemical profiles at marine hydrocarbon seeps1–3, and through ethane-dependent sulfate reduction in slurries4–7. Nevertheless, the micro...

Significance Microorganisms can oxidize hydrocarbons anaerobically, but the detection and quantification of this process in natural settings remains difficult, impeding reliable estimation of these processes at the global scale. We have used the technique of position-specific isotope analysis of propane and show that anaerobic biological degradatio...

The nanoSIMS-based chemical microscopy has been introduced in biology over a decade ago. The spatial distribution of elements and isotopes analyzed by nanoSIMS can be used to reconstruct images of biological samples with a resolution down to tens of nanometers, and can be also interpreted quantitatively. Currently, a unified approach for calculatio...

Coastal sediments are rich in conductive particles, possibly affecting microbial processes for which acetate is a central intermediate. In the methanogenic zone, acetate is consumed by methanogens and/or syntrophic acetate-oxidizing (SAO) consortia. SAO consortia live under extreme thermodynamic pressure, and their survival depends on successful pa...

Traditionally, the description of microorganisms starts with their isolation from an environmental sample. Many environmentally relevant anaerobic microorganisms grow very slowly, and often they rely on syntrophic interactions with other microorganisms. This impedes their isolation and characterization by classic microbiological techniques. We deve...

Coastal sediments are rich in conductive minerals, which could impact microbial processes for which acetate is a central intermediate. In the methanogenic zone, acetate is consumed by methanogens and/or syntrophic acetate oxidizing (SAO) consortia. SAO consortia live under extreme thermodynamic pressure and their survival depends on successful part...

The anaerobic formation and oxidation of methane involve unique enzymatic mechanisms and cofactors that are believed to be all specific for C1-compounds. Here we found that an anaerobic thermophilic enrichment culture composed of dense consortia of archaea and bacteria apparently uses partly similar pathways to oxidize the C4-hydrocarbon butane. Th...

The combination of stable isotope probing (SIP), NanoSIMS imaging and microbe identification via fluorescence in situ hybridization (FISH) is often used to link identity to function at the cellular level in microbial communities. Many opportunities remain for nanoSIP to identify metabolic interactions and nutrient fluxes within syntrophic associati...

Multi-element compound-specific isotope fractionation (ME-CSIA) has become a state-of-the-art approach for identifying biotransformation reactions. In the last decade, several studies focused on the combined analysis of carbon and hydrogen stable isotopes upon biodegradation of hydrocarbons due to its widespread environmental occurrence as contamin...

Saturated hydrocarbons (alkanes) and alkylated aromatic hydrocarbons are abundant environmental compounds. Hydrocarbons are primarily removed from the environment by biodegradation, a process usually associated with moderate carbon and significant hydrogen isotope fractionation allowing monitoring of biodegradation processes in the environment. Her...

Hydrocarbons are abundant in anoxic environments and pose biochemical challenges to their anaerobic degradation by microorganisms. Within the framework of the Priority Program 1319, investigations funded by the Deutsche Forschungsgemeinschaft on the anaerobic microbial degradation of hydrocarbons ranged from isolation and enrichment of hitherto unk...

Aerobic and anaerobic polycyclic aromatic hydrocarbon (PAH) biodegradation was characterized by compound specific stable isotope analysis (CSIA) of the carbon and hydrogen isotope effects of the enzymatic reactions initiating specific degradation pathways, using naphthalene and 2-methylnaphtalene as model compounds. Aerobic activation of naphthalen...

Hydrocarbons are apolar compounds devoid of functional groups and therefore exhibit (with some exceptions) low chemical reactivity at room temperature. Utilization of hydrocarbons by microorganisms as growth substrates is initiated by the introduction of a functional group. An astounding diversity of activation reactions has evolved in microorganis...

Hydrocarbons represent “energy-rich” growth substrates for aerobic microorganisms and in principle allow high growth yields. In contrast, the energy gain with hydrocarbons in many anaerobic microorganisms is very low. The maximum gain of energy per mol of hydrocarbon degraded in the catabolism is predicted from calculated ΔG values. Some anaerobic...

Crude oil and lipids greatly influence the structure and function of microbial communities, owing to merely physical effects such as hindering the diffusion of oxygen or light to communities trapped beneath oil layers, to toxicity of the highly soluble oil hydrocarbons, or to the utilization of hydrocarbons or lipids as growth substrates by microor...

Crude oils consist of complex mixtures of hydrocarbons, chemicals which are composed exclusively of carbon and hydrogen atoms. With a very low nitrogen content, crude oil contamination through natural seepage or anthropogenic activities leads to an overload of the affected environment with organic carbon. Degradation of oil hydrocarbons by microorg...

The short chain, gaseous alkanes ethane, propane, n- and iso-butane are released in significant amounts into the atmosphere, where they contribute to tropospheric chemistry and ozone formation. Biodegradation of gaseous alkanes by aerobic microorganisms, mostly bacteria and fungi isolated from terrestrial environments, has been known for several de...

The fate of cyclohexane, often used as a model compound for the biodegradation of cyclic alkanes due to its abundance in crude oils, in anoxic marine sediments has been poorly investigated. In the present study, we obtained an enrichment culture of cyclohexane-degrading sulfate-reducing bacteria from hydrocarbon-contaminated intertidal marine sedim...

The fate of cyclohexane, often used as a model compound for the biodegradation of cyclic alkanes due to its abundance in crude oils, in anoxic marine sediments has been poorly investigated. In the present study, we obtained an enrichment culture of cyclohexane-degrading sulfate-reducing bacteria from hydrocarbon-contaminated intertidal marine sedim...

Biogeochemical and microbiological data indicate that the anaerobic oxidation of non-methane hydrocarbons by sulfate-reducing bacteria (SRB) has an important role in carbon and sulfur cycling at marine seeps. Yet, little is known about the bacterial hydrocarbon degraders active in situ. Here, we provide the link between previous biogeochemical meas...

Bremen, University, Diss., 2005.

The anaerobic degradation of propane and butane is typically initiated by activation via addition to fumarate. Here we investigated the mechanism of activation under sulfate-reducing conditions by one pure culture (strain BuS5) and three enrichment cultures employing stable isotope analysis. Stable isotope fractionation was compared for cultures in...

The short-chain, non-methane hydrocarbons propane and butane can contribute significantly to the carbon and sulfur cycles in marine environments affected by oil or natural gas seepage. In the present study, we enriched and identified novel propane and butane-degrading sulfate reducers from marine oil and gas cold seeps in the Gulf of Mexico and Hyd...

The bacterial communities in the anoxic layer of a heavily polluted microbial mat and their growth on hydrocarbons under sulfate-reducing conditions were investigated. Microbial communities were dominated by members of Alphaproteobacteria (27% of the total rRNA), Planctomycetes (21.1%) and sulfate-reducing bacteria (SRB: 17.5%). 16S rRNA cloning re...

An anaerobic nitrate-reducing enrichment culture was established with a cyclic saturated petroleum hydrocarbon, cyclohexane, the fate of which in anoxic environments has been scarcely investigated. GC-MS showed cyclohexylsuccinate as a metabolite, in accordance with an anaerobic enzymatic activation of cyclohexane by carbon-carbon addition to fumar...

Benzene, the archetypal aromatic hydrocarbon is a common constituent of crude oil and oil-refined products. As such, it can enter the biosphere through natural oil seeps or as a consequence of exploitation of fossil fuel reservoirs. Benzene is chemically very stable, due to the stabilizing aromatic electron system and to the lack of functional grou...

Hydrocarbons represent “energy-rich” growth substrates for aerobic microorganisms and in principle allow high growth yields. In contrast, the energy gain with hydrocarbons in many anaerobic microorganisms is very low. The maximum gain of energy per mol of hydrocarbon degraded in the catabolism is predicted from calculated ΔG values. Some anaerobic...

Hydrocarbons are apolar compounds devoid of functional groups and therefore exhibit (with some exceptions) low chemical reactivity at room temperature. Utilization of hydrocarbons by microorganisms as growth substrates is initiated by the introduction of a functional group. An astounding diversity of activation reactions has evolved in microorganis...

The nitrogen cycling of Lake Cadagno was investigated by using a combination of biogeochemical and molecular ecological techniques. In the upper oxic freshwater zone inorganic nitrogen concentrations were low (up to approximately 3.4 microM nitrate at the base of the oxic zone), while in the lower anoxic zone there were high concentrations of ammon...

The anaerobic biodegradation of naphthalene, an aromatic hydrocarbon in tar and petroleum, has been repeatedly observed in environments but scarcely in pure cultures. To further explore the relationships and physiology of anaerobic naphthalene-degrading microorganisms, sulfate-reducing bacteria (SRB) were enriched from a Mediterranean sediment with...

The anaerobic biodegradation of benzene, a common constituent of petroleum and one of the least reactive aromatic hydrocarbons, is insufficiently understood with respect to the involved microorganisms and their metabolism. To study these aspects, sulfate-reducing bacteria were enriched with benzene as sole organic substrate using marine sediment as...

The short-chain hydrocarbons ethane, propane and butane are constituents of natural gas. They are usually assumed to be of thermochemical origin, but biological formation of ethane and propane has been also observed. Microbial utilization of short-chain hydrocarbons has been shown in some aerobic species but not in anaerobic species of bacteria. On...

INTRODUCTION Sulphate-reducing bacteria (SRB), or more generally speaking sulphate-reducing prokaryotes (SRP), are terminal oxidizers in the natural recycling of bio-organic compounds to CO2 in anoxic environments, in particular in marine sediments. SRP play this geochemically important role because they make use of a globally abundant electron ac...

Hydrocarbons shown to be degraded anaerobically by SRP are chemically rather diverse, as are the phylogenetic lineages where these capacities occur (Figs. 1, 3). There may be further, hitherto unrecognized capacities and species with respect to the anaerobic degradation of hydrocarbons with sulphate. Such apparent diversity may be viewed as the res...

Aerobic microbial degradation of pollutant oil (petroleum) in aquatic environments is often severely limited by the availability of combined nitrogen. We therefore studied whether the microbial community enriched in marine sediment microcosms with an added oil layer and exposure to light harboured nitrogenase activity. The acetylene reduction (AR)...

Paclele Mici is a terrestrial mud volcano field located in the Carpathian Mountains (Romania), where thermal alteration of sedimentary organic compounds leads to methane, higher hydrocarbons and other petroleum compounds that are continuously released into the environment. The hydrocarbons represent potential substrates for microorganisms. We studi...

Contamination of tidal sediment with oil and the development of microbial populations associated with oil was simulated in aquaria in the laboratory. Even distribution of a thin viscous mixture of oil and natural sediment over pristine sediment was a controllable method to achieve development of bioactive horizons (mat-like stratification) attribut...