The Experts below are selected from a list of 9918 Experts worldwide ranked by ideXlab platform

Yukio Imanishi - One of the best experts on this subject based on the ideXlab platform.

Elena Tamburini - One of the best experts on this subject based on the ideXlab platform.

  • biodiversity of new Surface Active Compound producing bacteria
    FEMS 2009, 2009
    Co-Authors: Claudio Ruggeri, Andrea Franzetti, Giuseppina Bestetti, P La Colla, M Berta, Manuela Pintus, Simona Sergi, Elena Tamburini
    Abstract:

    Background: Many prokaryotic and eukaryotic microorganisms synthesize a wide range of structurally different amphiphilic Surface Active Compounds (SACs). SACs find application in almost every industrial sectors. The research on microbial SACs has been confined, mostly, to few well-characterized Compounds produced by a small number of microbial genera. Until now, only few studies were concerned with the phylogenetic diversity of SAC-producing bacteria. Furthermore, the majority of the microbial producers described in literature has been isolated from a narrow range of environments, mainly undisturbed and hydrocarbon contaminated soils.

  • Isolation and characterisation of Surface Active Compound-producing bacteria from hydrocarbon-contaminated environments
    International Biodeterioration & Biodegradation, 2009
    Co-Authors: Claudio Ruggeri, Andrea Franzetti, Giuseppina Bestetti, Manuela Pintus, Simona Sergi, P Caredda, Paolo La Colla, Elena Tamburini
    Abstract:

    Abstract Bacteria able to produce Surface Active Compounds (SACs) were isolated from hydrocarbon-contaminated environments. The phylogenetic diversity of the isolates was evaluated by 16S rRNA gene analysis. The production of bioemulsifiers and biosurfactants was determined on strains representative of 18 different bacterial genera. Cupriavidus sp. BSNC28C produced extracellular biosurfactants which reduce the Surface tension into the culture medium up to 37.1 mN m−1. Sixteen strains, belonging to 11 different genera, released extracellular emulsifiers able to stabilise oil–water emulsions. Among them, the strains Bradyrhizobium sp. BSNC30A and Bosea sp. BSNC5B showed emulsification activities comparable to those of synthetic surfactants. Overall, the novel SAC-producing strains characterised in this work display promising features for the future development of economically efficient industrial-scale biotechnological processes.

  • Surface-Active Compounds and their role in the access to hydrocarbons in Gordonia strains.
    FEMS microbiology ecology, 2007
    Co-Authors: Andrea Franzetti, Giuseppina Bestetti, P Caredda, Paolo La Colla, Elena Tamburini
    Abstract:

    Three new bacterial strains (M22, BS25 and BS29) belonging to the Gordonia genus were isolated from a site chronically contaminated by diesel. Those Gordonia strains were able to grow using a wide range of straight and branched aliphatic hydrocarbons as carbon and energy sources and to produce at least two classes of Surface-Active Compounds. Emulsifying agents were released in the culture medium when bacteria grew both on hydrocarbons and water-soluble substrates. Cell-bound biosurfactants, which reduce the Surface tension, were produced on hydrocarbons; however, their production was significantly lower on water soluble substrates. The relationship of growth phase, Surface-Active Compound production and cell-Surface properties was analyzed in kinetic experiments on hydrocarbons. Gordonia sp. BS29 synthesized, and released extracellularly, bioemulsans during the exponential phase with n-hexadecane as carbon and energy source. The production of biosurfactants started in the exponential phase and their concentration increased during the following linear growth. Furthermore, the adhesion of bacterial cells to hydrocarbons decreased during growth. Our results led us to hypothesize a change in the mode by which Gordonia cells access the substrate during growth on hydrocarbons.

Alberto Striolo - One of the best experts on this subject based on the ideXlab platform.

  • emergent properties of antiagglomerant films control methane transport implications for hydrate management
    Langmuir, 2018
    Co-Authors: Francois Sicard, Tai Bui, Deepak Monteiro, Qiang Lan, Mark Ceglio, Charlotte Burress, Alberto Striolo
    Abstract:

    The relationship between collective properties and performance of antiagglomerants (AAs) used in hydrate management is handled using molecular dynamics simulations and enhanced sampling techniques. A thin film of AAs adsorbed at the interface between one flat sII methane hydrate substrate and a fluid hydrocarbon mixture containing methane and n-dodecane is studied. The AA considered is a Surface-Active Compound with a complex hydrophilic head that contains both amide and tertiary ammonium cation groups and hydrophobic tails. At a sufficiently high AA density, the interplay between the surfactant layer and the liquid hydrocarbon excludes methane from the interfacial region. In this scenario, we combine metadynamics and umbrella sampling frameworks to study accurately the free-energy landscape and the equilibrium rates associated with the transport of one methane molecule across the AA film. We observe that the local configurational changes of the liquid hydrocarbon packed within the AA film are associated with high free-energy barriers for methane transport. The time scales estimated for the transport of methane across the AA film can be, in some cases, comparable to those reported in the literature for the growth of hydrates, suggesting that one possible mechanism by which AAs delay the formation of hydrate plugs could be providing a barrier to methane transport. Considering the interplay between the structural design and collective properties of AAs might be of relevance to improve their performance in flow assurance.

  • emergent properties of antiagglomerant films control methane transport implications for hydrate management
    arXiv: Soft Condensed Matter, 2018
    Co-Authors: Francois Sicard, Tai Bui, Deepak Monteiro, Qiang Lan, Mark Ceglio, Charlotte Burress, Alberto Striolo
    Abstract:

    The relation between collective properties and performance of antiagglomerants (AAs) used in hydrate management is handled using molecular dynamics simulations and enhanced sampling techniques. A thin film of AAs adsorbed at the interface between one flat sII methane hydrate substrate and a fluid hydrocarbon mixture containing methane and n-dodecane is studied. The AA considered is a Surface-Active Compound with a complex hydrophilic head that contains both amide and tertiary ammonium cation groups and hydrophobic tails. At sufficiently high AA density, the interplay between the surfactant layer and the liquid hydrocarbon excludes methane from the interfacial region. In this scenario, we combine metadynamics and umbrella sampling frameworks to study accurately the free-energy landscape and the equilibrium rates associated with the transport of one methane molecule across the AA film. We observe that local configurational changes of the liquid hydrocarbon packed within the AA film are associated with high free-energy barriers for methane transport. The time scales estimated for the transport of methane across the AA film can be, in some cases, comparable to those reported in the literature for the growth of the hydrates, suggesting that one possible mechanism by which AAs delay the formation of hydrate plugs could be providing a barrier to methane transport. Considering the interplay between structural design and collective properties of AAs might be of relevance to improve their performance in flow assurance.

Takashi Kashiwagi - One of the best experts on this subject based on the ideXlab platform.

Francois Sicard - One of the best experts on this subject based on the ideXlab platform.

  • emergent properties of antiagglomerant films control methane transport implications for hydrate management
    Langmuir, 2018
    Co-Authors: Francois Sicard, Tai Bui, Deepak Monteiro, Qiang Lan, Mark Ceglio, Charlotte Burress, Alberto Striolo
    Abstract:

    The relationship between collective properties and performance of antiagglomerants (AAs) used in hydrate management is handled using molecular dynamics simulations and enhanced sampling techniques. A thin film of AAs adsorbed at the interface between one flat sII methane hydrate substrate and a fluid hydrocarbon mixture containing methane and n-dodecane is studied. The AA considered is a Surface-Active Compound with a complex hydrophilic head that contains both amide and tertiary ammonium cation groups and hydrophobic tails. At a sufficiently high AA density, the interplay between the surfactant layer and the liquid hydrocarbon excludes methane from the interfacial region. In this scenario, we combine metadynamics and umbrella sampling frameworks to study accurately the free-energy landscape and the equilibrium rates associated with the transport of one methane molecule across the AA film. We observe that the local configurational changes of the liquid hydrocarbon packed within the AA film are associated with high free-energy barriers for methane transport. The time scales estimated for the transport of methane across the AA film can be, in some cases, comparable to those reported in the literature for the growth of hydrates, suggesting that one possible mechanism by which AAs delay the formation of hydrate plugs could be providing a barrier to methane transport. Considering the interplay between the structural design and collective properties of AAs might be of relevance to improve their performance in flow assurance.

  • emergent properties of antiagglomerant films control methane transport implications for hydrate management
    arXiv: Soft Condensed Matter, 2018
    Co-Authors: Francois Sicard, Tai Bui, Deepak Monteiro, Qiang Lan, Mark Ceglio, Charlotte Burress, Alberto Striolo
    Abstract:

    The relation between collective properties and performance of antiagglomerants (AAs) used in hydrate management is handled using molecular dynamics simulations and enhanced sampling techniques. A thin film of AAs adsorbed at the interface between one flat sII methane hydrate substrate and a fluid hydrocarbon mixture containing methane and n-dodecane is studied. The AA considered is a Surface-Active Compound with a complex hydrophilic head that contains both amide and tertiary ammonium cation groups and hydrophobic tails. At sufficiently high AA density, the interplay between the surfactant layer and the liquid hydrocarbon excludes methane from the interfacial region. In this scenario, we combine metadynamics and umbrella sampling frameworks to study accurately the free-energy landscape and the equilibrium rates associated with the transport of one methane molecule across the AA film. We observe that local configurational changes of the liquid hydrocarbon packed within the AA film are associated with high free-energy barriers for methane transport. The time scales estimated for the transport of methane across the AA film can be, in some cases, comparable to those reported in the literature for the growth of the hydrates, suggesting that one possible mechanism by which AAs delay the formation of hydrate plugs could be providing a barrier to methane transport. Considering the interplay between structural design and collective properties of AAs might be of relevance to improve their performance in flow assurance.