The Experts below are selected from a list of 138 Experts worldwide ranked by ideXlab platform
David Pignol - One of the best experts on this subject based on the ideXlab platform.
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A Sensitive Magnetic Arsenite-Specific Biosensor Hosted in Magnetotactic Bacteria
Applied and Environmental Microbiology, 2020Co-Authors: Anissa Dieudonné, Sandra Prévéral, David PignolAbstract:According to the World Health Organization, arsenic is the water contaminant that affects the largest number of people worldwide. To limit its impact on the population, inexpensive, quick, and easy-to-use systems of detection are required. One promising solution could be the use of Whole-Cell biosensors, which have been extensively studied and could meet all these criteria even though they often lack sensitivity. Here, we investigated the benefit of using magnetotactic bacteria as Cellular chassis to design and build sensitive magnetic bacterial biosensors. Promoters potentially inducible by arsenic were first identified in silico within the genomes of two magnetotactic bacteria strains, Magnetospirillum magneticum AMB-1 and Magnetospirillum gryphiswaldense MSR-1. The ArsR-dependent regulation was confirmed by reverse transcription-PCR experiments. Biosensors built by transcriptional fusion between the arsenic-inducible promoters and the bacterial luciferase luxCDABE operon gave an element-specific response in 30 min with an arsenite detection limit of 0.5 mu M. After magnetic concentration, we improved the sensitivity of the biosensor by a factor of 50 to reach 10 nM, more than 1 order of magnitude below the recommended guidelines for arsenic in drinking water (0.13 mu M). Finally, we demonstrated the successful preservation of the magnetic bacterium biosensors by freeze-drying. IMPORTANCE Whole-Cell biosensors based on reporter genes can be designed for heavy metal detection but often require the optimization of their sensitivity and specific adaptations for practical use in the field. Magnetotactic bacteria as Cellular hosts for biosensors are interesting models, as their intrinsic magnetism permits them to be easily concentrated and entrapped to increase the arsenic-response signal. This paves the way for the development of sensitive and Immobilized Whole-Cell biosensors tailored for use in the field.
Hideki Fukuda - One of the best experts on this subject based on the ideXlab platform.
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Ethanolysis of rapeseed oil to produce biodiesel fuel catalyzed by Fusarium heterosporum lipase-expressing fungus Immobilized Whole-Cell biocatalysts
Journal of Molecular Catalysis B-enzymatic, 2010Co-Authors: Risa Koda, Hideki Fukuda, Shinji Hama, Kazunori Nakashima, Chiaki Ogino, Takao Numata, Sriappareddy Tamalampudi, Tsutomu Tanaka, Akihiko KondoAbstract:We demonstrated ethanolysis of rapeseed oil to produce biodiesel fuel using lipase-producing filamentous fungi Immobilized on biomass support particles (BSPs) as a Whole-Cell biocatalyst. We prepared two types of Whole-Cell biocatalyst: wild-type Rhizopus oryzae producing triacylglycerol lipase (w-ROL) and recombinant Aspergillus oryzae expressing Fusarium heterosporum lipase (r-FHL). Both w-ROL and r-FHL successfully catalyzed the ethanolysis of rapeseed oil, and the fatty acid ethyl ester yield was as high as 79% (w-ROL) or 94% (r-FHL). In the case of r-FHL, the residual monoglycerides (MGs) and diglycerides (DGs) were no more than 0.73 and 0.18%, respectively. In addition, r-FHL could be recycled for the ethanolysis of rapeseed oil, retaining over 85% fatty acid ethyl ester yield by the fifth cycle. r-FHL was revealed to be a promising catalyst for biodiesel production using rapeseed oil and ethanol.
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bioenergy sustainable fuels from biomass by yeast and fungal Whole Cell biocatalysts
Biochemical Engineering Journal, 2009Co-Authors: Hideki Fukuda, Akihiko Kondo, Sriappareddy TamalampudiAbstract:The dependency on depleting natural resources is a challenge for energy security that can be potentially answered by bioenergy. Bioenergy is derived from starchy and lignoCellulosic biomass in the form of bioethanol or from vegetable oils in the form of biodiesel fuel. The acid and enzymatic methods have been developed for the hydrolysis of biomass and for transesterification of plant oils. However, acid hydrolysis results in the production of unnatural compounds which have adverse effects on yeast fermentation. Recent advancements in the yeast Cell surface engineering developed strategies to genetically immobilize amylolytic, Cellulolytic and xylanolytic enzymes on yeast Cell surface for the production of fuel ethanol from biomass. Whereas in the case of biodiesel fuel production, alkali catalysis gives high levels of conversion in short reaction times. But complexity in the separation of produced biodiesel fuel from glycerol by-product led to intensive research on lipase enzyme and Immobilized Whole-Cell biocatalysts. This system facilitates the easy separation of glycerol with the advantage of cost effectiveness. This review gives an insight in to the recent technological developments in the production of bioenergy, i.e., bioethanol and biodiesel fuel using surface engineered yeast and Whole-Cell biocatalysts.
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enzymatic production of biodiesel from jatropha oil a comparative study of Immobilized Whole Cell and commercial lipases as a biocatalyst
Biochemical Engineering Journal, 2008Co-Authors: Sriappareddy Tamalampudi, Akihiko Kondo, Shinji Hama, Takao Numata, Mahabubur Rahman Talukder, Hideki FukudaAbstract:The large percentage of biodiesel fuel (BDF) cost associated with feedstock oil and enzyme. In order to reduce the cost of BDF production, the lipase producing Whole Cells of Rhizopus oryzae (ROL) Immobilized onto biomass support particles (BSPs) was used for the production of BDF from relatively low cost non-edible oil from the seeds of Jatropha curcas. The activity of ROL was compared with that of commercially available most effective lipase (Novozym 435). Different alcohols as a hydroxyl donor are tested, and methanolysis of Jatropha oil progresses faster than other alcoholysis regardless of lipases used. The maximum methyl esters content in the reaction mixture reaches 80 wt.% after 60 h using ROL, whereas it is 76% after 90 It using Novozym 435. Both the lipases can be used for repeated batches and both lipases exhibit more than 90% of their initial activities after five cycles. Our results suggest that Whole-Cell ROL Immobilized on BSP is a promising biocatalyst for producing BDF from oil. (C) 2007 Elsevier B.V. All rights reserved.
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preparation of high activity Whole Cell biocatalysts by permeabilization of recombinant yeasts with alcohol
Journal of Bioscience and Bioengineering, 2000Co-Authors: Yan Liu, Akihiko Kondo, Yasuya Fujita, Hideki FukudaAbstract:Abstract Recombinant yeast Cells intraCellularly overexpressing three different enzymes were permeabilized with alcohol under various conditions. The effects of enzyme stability in alcohol and enzyme molecular weight on the activities of permeabilized Cells and enzyme leakage during incubation were examined. Saccharomyces cerevisiae YPH250 overexpressing glyoxalase I (GloI), S. cerevisiae MT8-1 overexpressing isocitrate lyase (ICL), and Pichia pastoris GS115 overexpressing β-galactosidase (β-gal) were used as model recombinant yeast systems. In all cases, the percentage of alcohol used for the treatment significantly affected the activity of permeabilized Whole Cell biocatalysts; Cells showed high activity when treated with 40% isopropyl alcohol. The activity of Whole Cell biocatalysts was also significantly affected by the stability of the enzyme in alcohol solution; permeabilized yeast Cells overexpressing ICL, which had low stability, showed rather low activity. Although the enzyme leakage from permeabilized Cells was rather low in all cases, the molecular weight of the enzyme appeared to affect the extent of enzyme leakage during incubation. Permeabilized Cells of P. pastoris overexpressing β-gal (540 kDa) retained particularly high activity during incubation and could be used as an Immobilized Whole Cell biocatalysts.
Anissa Dieudonné - One of the best experts on this subject based on the ideXlab platform.
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A Sensitive Magnetic Arsenite-Specific Biosensor Hosted in Magnetotactic Bacteria
Applied and Environmental Microbiology, 2020Co-Authors: Anissa Dieudonné, Sandra Prévéral, David PignolAbstract:According to the World Health Organization, arsenic is the water contaminant that affects the largest number of people worldwide. To limit its impact on the population, inexpensive, quick, and easy-to-use systems of detection are required. One promising solution could be the use of Whole-Cell biosensors, which have been extensively studied and could meet all these criteria even though they often lack sensitivity. Here, we investigated the benefit of using magnetotactic bacteria as Cellular chassis to design and build sensitive magnetic bacterial biosensors. Promoters potentially inducible by arsenic were first identified in silico within the genomes of two magnetotactic bacteria strains, Magnetospirillum magneticum AMB-1 and Magnetospirillum gryphiswaldense MSR-1. The ArsR-dependent regulation was confirmed by reverse transcription-PCR experiments. Biosensors built by transcriptional fusion between the arsenic-inducible promoters and the bacterial luciferase luxCDABE operon gave an element-specific response in 30 min with an arsenite detection limit of 0.5 mu M. After magnetic concentration, we improved the sensitivity of the biosensor by a factor of 50 to reach 10 nM, more than 1 order of magnitude below the recommended guidelines for arsenic in drinking water (0.13 mu M). Finally, we demonstrated the successful preservation of the magnetic bacterium biosensors by freeze-drying. IMPORTANCE Whole-Cell biosensors based on reporter genes can be designed for heavy metal detection but often require the optimization of their sensitivity and specific adaptations for practical use in the field. Magnetotactic bacteria as Cellular hosts for biosensors are interesting models, as their intrinsic magnetism permits them to be easily concentrated and entrapped to increase the arsenic-response signal. This paves the way for the development of sensitive and Immobilized Whole-Cell biosensors tailored for use in the field.
László Poppe - One of the best experts on this subject based on the ideXlab platform.
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Conservation of the Biocatalytic Activity of Whole Yeast Cells by Supported Sol – Gel Entrapment for Efficient Acyloin Condensation
Periodica Polytechnica Chemical Engineering, 2019Co-Authors: László Nagy-győr, Emese Farkas, Csaba Paizs, László Poppe, Viktória Bódai, Gábor Hornyánszky, Mihai Lăcătuș, Gergő Tóth, Dániel Incze, Diána Balogh-weiserAbstract:In this study, an efficient and generally applicable 2nd generation sol – gel entrapment method was developed for immobilization of yeastCells. Cells of Lodderomyces elongisporus, Candida norvegica, Debaryomyces fabryi, Pichia carsonii strains in admixture with hollow silica microspheres support were Immobilized in sol – gel matrix obtained from polycondensation of tetraethoxysilane. As biocatalysts in theselective acyloin condensation of benzaldehyde catalyzed by pyruvate decarboxylase of the yeast, the novel Immobilized Whole-Cell preparations were compared to other states of the Cells such as freshly harvested wet Cell paste, lyophilized Cells and sol – gel entrapped preparations without hollow silica microspheres support. Reusability and storability studies designated this novel 2nd generation sol – gel method as a promising alternative for solid formulation of Whole-Cells bypassing expensive and difficult downstream steps while providing easy-to-handle and stable biocatalysts with long-term preservation of the biocatalytic activity.
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Immobilized Whole-Cell transaminase biocatalysts for continuous-flow kinetic resolution of amines
Catalysts, 2019Co-Authors: Zsófia Molnár, Emese Farkas, Ágnes Lakó, Balázs Erdélyi, Wolfgang Kroutil, Beáta G. Vértessy, Csaba Paizs, László PoppeAbstract:Immobilization of transaminases creates promising biocatalysts for production of chiral amines in batch or continuous-flow mode reactions. E. coli Cells containing overexpressed transaminases of various selectivities and hollow silica microspheres as supporting agent were Immobilized by an improved sol-gel process to produce Immobilized transaminase biocatalysts with suitable stability and mechanical properties for continuous-flow applications. The Immobilized Cell-based transaminase biocatalyst proved to be durable and easy-to-use in kinetic resolution of four racemic amines 1a–d. The batch and continuous-flow mode kinetic resolutions with transaminase biocatalyst of opposite stereopreference provided access to both enantiomers of the corresponding amines. By using the most suitable Immobilized transaminase biocatalysts, this study describes the first transaminase-based approach for the production of both pure enantiomers of 1-(3,4-dimethoxyphenyl)ethan-1-amine 1d.
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Co-Immobilized Whole Cells with ω-Transaminase and Ketoreductase Activities for Continuous-Flow Cascade Reactions.
Chembiochem : a European journal of chemical biology, 2018Co-Authors: László Nagy-győr, Balázs Erdélyi, Csaba Paizs, Emese Abaházi, Viktória Bódai, Péter Sátorhelyi, Diána Balogh-weiser, Gábor Hornyánszky, László PoppeAbstract:An improved sol-gel process involving the use of hollow silica microspheres as a supporting additive was applied for the co-immobilization of Whole Cells of Escherichia coli with Chromobacterium violaceum ω-transaminase activity and Lodderomyces elongisporus with ketoreductase activity. The co-Immobilized Cells with two different biocatalytic activities could perform a cascade of reactions to convert racemic 4-phenylbutan-2-amine or heptan-2-amine into a nearly equimolar mixture of the corresponding enantiomerically pure R amine and S alcohol even in continuous-flow mode. The novel co-Immobilized Whole-Cell system proved to be an easy-to-store and durable biocatalyst.
Akihiko Kondo - One of the best experts on this subject based on the ideXlab platform.
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Ethanolysis of rapeseed oil to produce biodiesel fuel catalyzed by Fusarium heterosporum lipase-expressing fungus Immobilized Whole-Cell biocatalysts
Journal of Molecular Catalysis B-enzymatic, 2010Co-Authors: Risa Koda, Hideki Fukuda, Shinji Hama, Kazunori Nakashima, Chiaki Ogino, Takao Numata, Sriappareddy Tamalampudi, Tsutomu Tanaka, Akihiko KondoAbstract:We demonstrated ethanolysis of rapeseed oil to produce biodiesel fuel using lipase-producing filamentous fungi Immobilized on biomass support particles (BSPs) as a Whole-Cell biocatalyst. We prepared two types of Whole-Cell biocatalyst: wild-type Rhizopus oryzae producing triacylglycerol lipase (w-ROL) and recombinant Aspergillus oryzae expressing Fusarium heterosporum lipase (r-FHL). Both w-ROL and r-FHL successfully catalyzed the ethanolysis of rapeseed oil, and the fatty acid ethyl ester yield was as high as 79% (w-ROL) or 94% (r-FHL). In the case of r-FHL, the residual monoglycerides (MGs) and diglycerides (DGs) were no more than 0.73 and 0.18%, respectively. In addition, r-FHL could be recycled for the ethanolysis of rapeseed oil, retaining over 85% fatty acid ethyl ester yield by the fifth cycle. r-FHL was revealed to be a promising catalyst for biodiesel production using rapeseed oil and ethanol.
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bioenergy sustainable fuels from biomass by yeast and fungal Whole Cell biocatalysts
Biochemical Engineering Journal, 2009Co-Authors: Hideki Fukuda, Akihiko Kondo, Sriappareddy TamalampudiAbstract:The dependency on depleting natural resources is a challenge for energy security that can be potentially answered by bioenergy. Bioenergy is derived from starchy and lignoCellulosic biomass in the form of bioethanol or from vegetable oils in the form of biodiesel fuel. The acid and enzymatic methods have been developed for the hydrolysis of biomass and for transesterification of plant oils. However, acid hydrolysis results in the production of unnatural compounds which have adverse effects on yeast fermentation. Recent advancements in the yeast Cell surface engineering developed strategies to genetically immobilize amylolytic, Cellulolytic and xylanolytic enzymes on yeast Cell surface for the production of fuel ethanol from biomass. Whereas in the case of biodiesel fuel production, alkali catalysis gives high levels of conversion in short reaction times. But complexity in the separation of produced biodiesel fuel from glycerol by-product led to intensive research on lipase enzyme and Immobilized Whole-Cell biocatalysts. This system facilitates the easy separation of glycerol with the advantage of cost effectiveness. This review gives an insight in to the recent technological developments in the production of bioenergy, i.e., bioethanol and biodiesel fuel using surface engineered yeast and Whole-Cell biocatalysts.
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enzymatic production of biodiesel from jatropha oil a comparative study of Immobilized Whole Cell and commercial lipases as a biocatalyst
Biochemical Engineering Journal, 2008Co-Authors: Sriappareddy Tamalampudi, Akihiko Kondo, Shinji Hama, Takao Numata, Mahabubur Rahman Talukder, Hideki FukudaAbstract:The large percentage of biodiesel fuel (BDF) cost associated with feedstock oil and enzyme. In order to reduce the cost of BDF production, the lipase producing Whole Cells of Rhizopus oryzae (ROL) Immobilized onto biomass support particles (BSPs) was used for the production of BDF from relatively low cost non-edible oil from the seeds of Jatropha curcas. The activity of ROL was compared with that of commercially available most effective lipase (Novozym 435). Different alcohols as a hydroxyl donor are tested, and methanolysis of Jatropha oil progresses faster than other alcoholysis regardless of lipases used. The maximum methyl esters content in the reaction mixture reaches 80 wt.% after 60 h using ROL, whereas it is 76% after 90 It using Novozym 435. Both the lipases can be used for repeated batches and both lipases exhibit more than 90% of their initial activities after five cycles. Our results suggest that Whole-Cell ROL Immobilized on BSP is a promising biocatalyst for producing BDF from oil. (C) 2007 Elsevier B.V. All rights reserved.
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preparation of high activity Whole Cell biocatalysts by permeabilization of recombinant yeasts with alcohol
Journal of Bioscience and Bioengineering, 2000Co-Authors: Yan Liu, Akihiko Kondo, Yasuya Fujita, Hideki FukudaAbstract:Abstract Recombinant yeast Cells intraCellularly overexpressing three different enzymes were permeabilized with alcohol under various conditions. The effects of enzyme stability in alcohol and enzyme molecular weight on the activities of permeabilized Cells and enzyme leakage during incubation were examined. Saccharomyces cerevisiae YPH250 overexpressing glyoxalase I (GloI), S. cerevisiae MT8-1 overexpressing isocitrate lyase (ICL), and Pichia pastoris GS115 overexpressing β-galactosidase (β-gal) were used as model recombinant yeast systems. In all cases, the percentage of alcohol used for the treatment significantly affected the activity of permeabilized Whole Cell biocatalysts; Cells showed high activity when treated with 40% isopropyl alcohol. The activity of Whole Cell biocatalysts was also significantly affected by the stability of the enzyme in alcohol solution; permeabilized yeast Cells overexpressing ICL, which had low stability, showed rather low activity. Although the enzyme leakage from permeabilized Cells was rather low in all cases, the molecular weight of the enzyme appeared to affect the extent of enzyme leakage during incubation. Permeabilized Cells of P. pastoris overexpressing β-gal (540 kDa) retained particularly high activity during incubation and could be used as an Immobilized Whole Cell biocatalysts.
