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Ines A C Pereira - One of the best experts on this subject based on the ideXlab platform.

  • characterization of the desulfovibrio desulfuricans atcc 27774 dsrmkjop complex a membrane bound redox complex involved in the sulfate respiratory pathway
    Biochemistry, 2006
    Co-Authors: Ricardo H Pires, Miguel Teixeira, Francisco Morais, Sofia S Venceslau, And Antonio V Xavier, Ines A C Pereira
    Abstract:

    Sulfate-reducing organisms use sulfate as an electron acceptor in an anaerobic respiratory process. Despite their ubiquitous occurrence, sulfate respiration is still poorly characterized. Genome analysis of sulfate-reducing organisms sequenced to date permitted the identification of only two strictly conserved membrane complexes. We report here the purification and characterization of one of these complexes, DsrMKJOP, from Desulfovibrio desulfuricans ATCC 27774. The complex has hemes of the c and b types and several iron-sulfur centers. The corresponding genes in the genome of Desulfovibrio vulgaris were analyzed. dsrM encodes an integral membrane cytochrome b; dsrK encodes a protein homologous to the HdrD subunit of heterodisulfide reductase; dsrJ encodes a triheme periplasmic cytochrome c; dsrO encodes a periplasmic FeS protein; and dsrM encodes another integral membrane protein. Sequence analysis and EPR studies indicate that DsrJ belongs to a novel family of multiheme cytochromes c and that its three hemes have different types of coordination, one bis-His, one His/Met, and the third a very unusual His/Cys coordination. The His/Cys-coordinated heme is only partially reduced by dithionite. About 40% of the hemes are reduced by Menadiol, but no reduction is observed upon treatment with H2 and hydrogenase, irrespective of the presence of cytochrome c3. The aerobically isolated Dsr complex displays an EPR signal with similar characteristics to the catalytic [4Fe-4S]3+ species observed in heterodisulfide reductases. Further five different [4Fe-4S](2+/1+) centers are observed during a redox titration followed by EPR. The role of the DsrMKJOP complex in the sulfate respiratory chain of Desulfovibrio spp. is discussed.

  • a novel membrane bound respiratory complex from desulfovibrio desulfuricans atcc 27774
    Biochimica et Biophysica Acta, 2003
    Co-Authors: Ricardo H Pires, Antonio V Xavier, Miguel Teixeira, Ligia M Saraiva, Alexandra Lourenco, Francisco Morais, Ines A C Pereira
    Abstract:

    Abstract In the anaerobic respiration of sulfate, performed by sulfate-reducing prokaryotes, reduction of the terminal electron acceptor takes place in the cytoplasm. The membrane-associated electron transport chain that feeds electrons to the cytoplasmic reductases is still very poorly characterized. In this study we report the isolation and characterization of a novel membrane-bound redox complex from Desulfovibrio desulfuricans ATCC 27774. This complex is formed by three subunits, and contains two hemes b , two FAD groups and several iron–sulfur centers. The two hemes b are low-spin, with macroscopic redox potentials of +75 and −20 mV at pH 7.6. Both hemes are reduced by Menadiol, a menaquinone analogue, indicating a function for this complex in the respiratory electron-transport chain. EPR studies of the as-isolated and dithionite-reduced complex support the presence of a [3Fe–4S] 1+/0 center and at least four [4Fe–4S] 2+/1+ centers. Cloning of the genes coding for the complex subunits revealed that they form a putative transcription unit and have homology to subunits of heterodisulfide reductases (Hdr). The first and second genes code for soluble proteins that have homology to HdrA, whereas the third gene codes for a novel type of membrane-associated protein that contains both a hydrophobic domain with homology to the heme b protein HdrE and a hydrophilic domain with homology to the iron–sulfur protein HdrC. Homologous operons are found in the genomes of other sulfate-reducing organisms and in the genome of the green-sulfur bacterium Chlorobium tepidum TLS. The isolated complex is the first example of a new family of respiratory complexes present in anaerobic prokaryotes.

Ricardo H Pires - One of the best experts on this subject based on the ideXlab platform.

  • characterization of the desulfovibrio desulfuricans atcc 27774 dsrmkjop complex a membrane bound redox complex involved in the sulfate respiratory pathway
    Biochemistry, 2006
    Co-Authors: Ricardo H Pires, Miguel Teixeira, Francisco Morais, Sofia S Venceslau, And Antonio V Xavier, Ines A C Pereira
    Abstract:

    Sulfate-reducing organisms use sulfate as an electron acceptor in an anaerobic respiratory process. Despite their ubiquitous occurrence, sulfate respiration is still poorly characterized. Genome analysis of sulfate-reducing organisms sequenced to date permitted the identification of only two strictly conserved membrane complexes. We report here the purification and characterization of one of these complexes, DsrMKJOP, from Desulfovibrio desulfuricans ATCC 27774. The complex has hemes of the c and b types and several iron-sulfur centers. The corresponding genes in the genome of Desulfovibrio vulgaris were analyzed. dsrM encodes an integral membrane cytochrome b; dsrK encodes a protein homologous to the HdrD subunit of heterodisulfide reductase; dsrJ encodes a triheme periplasmic cytochrome c; dsrO encodes a periplasmic FeS protein; and dsrM encodes another integral membrane protein. Sequence analysis and EPR studies indicate that DsrJ belongs to a novel family of multiheme cytochromes c and that its three hemes have different types of coordination, one bis-His, one His/Met, and the third a very unusual His/Cys coordination. The His/Cys-coordinated heme is only partially reduced by dithionite. About 40% of the hemes are reduced by Menadiol, but no reduction is observed upon treatment with H2 and hydrogenase, irrespective of the presence of cytochrome c3. The aerobically isolated Dsr complex displays an EPR signal with similar characteristics to the catalytic [4Fe-4S]3+ species observed in heterodisulfide reductases. Further five different [4Fe-4S](2+/1+) centers are observed during a redox titration followed by EPR. The role of the DsrMKJOP complex in the sulfate respiratory chain of Desulfovibrio spp. is discussed.

  • a novel membrane bound respiratory complex from desulfovibrio desulfuricans atcc 27774
    Biochimica et Biophysica Acta, 2003
    Co-Authors: Ricardo H Pires, Antonio V Xavier, Miguel Teixeira, Ligia M Saraiva, Alexandra Lourenco, Francisco Morais, Ines A C Pereira
    Abstract:

    Abstract In the anaerobic respiration of sulfate, performed by sulfate-reducing prokaryotes, reduction of the terminal electron acceptor takes place in the cytoplasm. The membrane-associated electron transport chain that feeds electrons to the cytoplasmic reductases is still very poorly characterized. In this study we report the isolation and characterization of a novel membrane-bound redox complex from Desulfovibrio desulfuricans ATCC 27774. This complex is formed by three subunits, and contains two hemes b , two FAD groups and several iron–sulfur centers. The two hemes b are low-spin, with macroscopic redox potentials of +75 and −20 mV at pH 7.6. Both hemes are reduced by Menadiol, a menaquinone analogue, indicating a function for this complex in the respiratory electron-transport chain. EPR studies of the as-isolated and dithionite-reduced complex support the presence of a [3Fe–4S] 1+/0 center and at least four [4Fe–4S] 2+/1+ centers. Cloning of the genes coding for the complex subunits revealed that they form a putative transcription unit and have homology to subunits of heterodisulfide reductases (Hdr). The first and second genes code for soluble proteins that have homology to HdrA, whereas the third gene codes for a novel type of membrane-associated protein that contains both a hydrophobic domain with homology to the heme b protein HdrE and a hydrophilic domain with homology to the iron–sulfur protein HdrC. Homologous operons are found in the genomes of other sulfate-reducing organisms and in the genome of the green-sulfur bacterium Chlorobium tepidum TLS. The isolated complex is the first example of a new family of respiratory complexes present in anaerobic prokaryotes.

Francisco Morais - One of the best experts on this subject based on the ideXlab platform.

  • characterization of the desulfovibrio desulfuricans atcc 27774 dsrmkjop complex a membrane bound redox complex involved in the sulfate respiratory pathway
    Biochemistry, 2006
    Co-Authors: Ricardo H Pires, Miguel Teixeira, Francisco Morais, Sofia S Venceslau, And Antonio V Xavier, Ines A C Pereira
    Abstract:

    Sulfate-reducing organisms use sulfate as an electron acceptor in an anaerobic respiratory process. Despite their ubiquitous occurrence, sulfate respiration is still poorly characterized. Genome analysis of sulfate-reducing organisms sequenced to date permitted the identification of only two strictly conserved membrane complexes. We report here the purification and characterization of one of these complexes, DsrMKJOP, from Desulfovibrio desulfuricans ATCC 27774. The complex has hemes of the c and b types and several iron-sulfur centers. The corresponding genes in the genome of Desulfovibrio vulgaris were analyzed. dsrM encodes an integral membrane cytochrome b; dsrK encodes a protein homologous to the HdrD subunit of heterodisulfide reductase; dsrJ encodes a triheme periplasmic cytochrome c; dsrO encodes a periplasmic FeS protein; and dsrM encodes another integral membrane protein. Sequence analysis and EPR studies indicate that DsrJ belongs to a novel family of multiheme cytochromes c and that its three hemes have different types of coordination, one bis-His, one His/Met, and the third a very unusual His/Cys coordination. The His/Cys-coordinated heme is only partially reduced by dithionite. About 40% of the hemes are reduced by Menadiol, but no reduction is observed upon treatment with H2 and hydrogenase, irrespective of the presence of cytochrome c3. The aerobically isolated Dsr complex displays an EPR signal with similar characteristics to the catalytic [4Fe-4S]3+ species observed in heterodisulfide reductases. Further five different [4Fe-4S](2+/1+) centers are observed during a redox titration followed by EPR. The role of the DsrMKJOP complex in the sulfate respiratory chain of Desulfovibrio spp. is discussed.

  • a novel membrane bound respiratory complex from desulfovibrio desulfuricans atcc 27774
    Biochimica et Biophysica Acta, 2003
    Co-Authors: Ricardo H Pires, Antonio V Xavier, Miguel Teixeira, Ligia M Saraiva, Alexandra Lourenco, Francisco Morais, Ines A C Pereira
    Abstract:

    Abstract In the anaerobic respiration of sulfate, performed by sulfate-reducing prokaryotes, reduction of the terminal electron acceptor takes place in the cytoplasm. The membrane-associated electron transport chain that feeds electrons to the cytoplasmic reductases is still very poorly characterized. In this study we report the isolation and characterization of a novel membrane-bound redox complex from Desulfovibrio desulfuricans ATCC 27774. This complex is formed by three subunits, and contains two hemes b , two FAD groups and several iron–sulfur centers. The two hemes b are low-spin, with macroscopic redox potentials of +75 and −20 mV at pH 7.6. Both hemes are reduced by Menadiol, a menaquinone analogue, indicating a function for this complex in the respiratory electron-transport chain. EPR studies of the as-isolated and dithionite-reduced complex support the presence of a [3Fe–4S] 1+/0 center and at least four [4Fe–4S] 2+/1+ centers. Cloning of the genes coding for the complex subunits revealed that they form a putative transcription unit and have homology to subunits of heterodisulfide reductases (Hdr). The first and second genes code for soluble proteins that have homology to HdrA, whereas the third gene codes for a novel type of membrane-associated protein that contains both a hydrophobic domain with homology to the heme b protein HdrE and a hydrophilic domain with homology to the iron–sulfur protein HdrC. Homologous operons are found in the genomes of other sulfate-reducing organisms and in the genome of the green-sulfur bacterium Chlorobium tepidum TLS. The isolated complex is the first example of a new family of respiratory complexes present in anaerobic prokaryotes.

Miguel Teixeira - One of the best experts on this subject based on the ideXlab platform.

  • characterization of the desulfovibrio desulfuricans atcc 27774 dsrmkjop complex a membrane bound redox complex involved in the sulfate respiratory pathway
    Biochemistry, 2006
    Co-Authors: Ricardo H Pires, Miguel Teixeira, Francisco Morais, Sofia S Venceslau, And Antonio V Xavier, Ines A C Pereira
    Abstract:

    Sulfate-reducing organisms use sulfate as an electron acceptor in an anaerobic respiratory process. Despite their ubiquitous occurrence, sulfate respiration is still poorly characterized. Genome analysis of sulfate-reducing organisms sequenced to date permitted the identification of only two strictly conserved membrane complexes. We report here the purification and characterization of one of these complexes, DsrMKJOP, from Desulfovibrio desulfuricans ATCC 27774. The complex has hemes of the c and b types and several iron-sulfur centers. The corresponding genes in the genome of Desulfovibrio vulgaris were analyzed. dsrM encodes an integral membrane cytochrome b; dsrK encodes a protein homologous to the HdrD subunit of heterodisulfide reductase; dsrJ encodes a triheme periplasmic cytochrome c; dsrO encodes a periplasmic FeS protein; and dsrM encodes another integral membrane protein. Sequence analysis and EPR studies indicate that DsrJ belongs to a novel family of multiheme cytochromes c and that its three hemes have different types of coordination, one bis-His, one His/Met, and the third a very unusual His/Cys coordination. The His/Cys-coordinated heme is only partially reduced by dithionite. About 40% of the hemes are reduced by Menadiol, but no reduction is observed upon treatment with H2 and hydrogenase, irrespective of the presence of cytochrome c3. The aerobically isolated Dsr complex displays an EPR signal with similar characteristics to the catalytic [4Fe-4S]3+ species observed in heterodisulfide reductases. Further five different [4Fe-4S](2+/1+) centers are observed during a redox titration followed by EPR. The role of the DsrMKJOP complex in the sulfate respiratory chain of Desulfovibrio spp. is discussed.

  • a novel membrane bound respiratory complex from desulfovibrio desulfuricans atcc 27774
    Biochimica et Biophysica Acta, 2003
    Co-Authors: Ricardo H Pires, Antonio V Xavier, Miguel Teixeira, Ligia M Saraiva, Alexandra Lourenco, Francisco Morais, Ines A C Pereira
    Abstract:

    Abstract In the anaerobic respiration of sulfate, performed by sulfate-reducing prokaryotes, reduction of the terminal electron acceptor takes place in the cytoplasm. The membrane-associated electron transport chain that feeds electrons to the cytoplasmic reductases is still very poorly characterized. In this study we report the isolation and characterization of a novel membrane-bound redox complex from Desulfovibrio desulfuricans ATCC 27774. This complex is formed by three subunits, and contains two hemes b , two FAD groups and several iron–sulfur centers. The two hemes b are low-spin, with macroscopic redox potentials of +75 and −20 mV at pH 7.6. Both hemes are reduced by Menadiol, a menaquinone analogue, indicating a function for this complex in the respiratory electron-transport chain. EPR studies of the as-isolated and dithionite-reduced complex support the presence of a [3Fe–4S] 1+/0 center and at least four [4Fe–4S] 2+/1+ centers. Cloning of the genes coding for the complex subunits revealed that they form a putative transcription unit and have homology to subunits of heterodisulfide reductases (Hdr). The first and second genes code for soluble proteins that have homology to HdrA, whereas the third gene codes for a novel type of membrane-associated protein that contains both a hydrophobic domain with homology to the heme b protein HdrE and a hydrophilic domain with homology to the iron–sulfur protein HdrC. Homologous operons are found in the genomes of other sulfate-reducing organisms and in the genome of the green-sulfur bacterium Chlorobium tepidum TLS. The isolated complex is the first example of a new family of respiratory complexes present in anaerobic prokaryotes.

Soldevila Fàbrega Andreu - One of the best experts on this subject based on the ideXlab platform.

  • Alternatives biotecnològiques a la síntesi química de la vitamina K3
    'Universitat Autonoma de Barcelona', 2004
    Co-Authors: Soldevila Fàbrega Andreu
    Abstract:

    Aquesta tesi tracta l'estudi de la producció de la vitamina K3 des d'un punt de vista biotecnològic amb l'objectiu de plantejar noves alternatives a la síntesis química clàssica d'aquesta vitamina.La síntesi clàssica de la vitamina K3 es realitza per un procediment químic que comporta una oxidació del 2-metilnaftalè com a material de partida, mitjançant un agent oxidant molt fort, el dicromat sòdic, en un medi que conté àcid sulfúric, creant-se una reacció que genera una elevadíssima quantitat de residus de crom en aigües àcides.Així doncs es tracta d'una reacció molt contaminant que alhora té unes limitacions des del punt de vista químic molt important, com és la no utilització d'un catalitzador, la generació de grans quantitats de residus, així com la formació d'un isòmer de la vitamina K3, la 6-metil-1,4-naftoquinona, de manera que es produeix un compost no biològicament actiu, del qual cal desfer-se mitjançant dificultosos processos de purificació.Els experiments realitzats en aquest treball van estar dirigits cap a la solució d'aquests problemes, és a dir, la utilització de biocatalitzadors en unes condicions suaus per a minimitzar l'impacte ambiental del procediment de síntesi , així com la millora de la selectivitat de la reacció, eliminantse la formació de l'isòmer de la vitamina K3, punt clau per a l'èxit d'aquest nou sistema de síntesi.Amb aquests objectius es va treballar amb microorganismes salvatges, així com amb microorganismes de col.leccions internacionals, fins que es va poder determinar que dos microorganismes salvatges aïllats del producte de partida de la reacció, el 2-metilnaftalè, així com tres soques de les col.leccions internacionals, eren capaços de produir vitamina K3 a partir d'aquest substracte. Un cop obtingudes les soques productores de vitamina K3 es va poder determinar el mecanisme de la reacció, que indicava la formació dels intermediaris 2-metil-1-naftol i 2-metil-4-naftol, seguit del Menadiol i finalment la formació de vitamina K3. També es va poder dur a terme la determinació de que els microorganismes productors de vitamina K3 tenien un 100% de selectivitat pel que fa a la formació de quinones, evitantse la formació de l'isòmer no desitjat, fet determinant per a l'interès del món químic-farmacèutic en una reacció d'aquest tipus. Es van poder mostrar diferents alternatives de síntesi d'aquesta vitamina utilitzant sistemes enzimàtics, cèl.lules senceres actives i cèl.lules senceres no proliferants, essent la producció amb Bacillus subtilis i Bacillus cereus biotip I en condicions de no proliferació en glucosa, les millor condicions de productivitat.Des del punt de vista dels estudis mol.leculars, es va poder determinar que la proteïna responsable de la síntesi de vitamina K3, utilitzant com a substracte el 2-metil-1-naftol, era la citocrom aa3-600quinol oxidasa de Bacillus subtilis , però no es va poder determinar la proteïna responsable del primer pas de la reacció, l'oxidació del 2-metilnaftalè a 2-metil-1-naftol.Els resultats obtinguts permeten veure un ventall de possibilitats que donen alternatives reals als processos clàssics de síntesi de la vitamina K3, tot i que són processos en els quals encara s'ha de treballar molt per augmentar-ne la productivitat fins a uns nivells òptims.The classical synthesis of vitamin K3 is done by a chemical process consisting of an oxidation of the substrate, 2-methylnaphtalene, with a powerful oxidizing agent such as sodium dichromate in a sulphuric acid medium, which leads to a stechiometric reaction that generates an extremely high amount of chromium waste in acidic waters.This process is extremely polluting and at the same time, from a chemical point of view, its limitations are very important. The most important limitations are the low atom echonomy, because no catalysis is achieved as it is a stechiometric reaction that produces a great amount of waste, and the production of an isomer(6-methyl-1,4-naphtoquinone) of the vitamin, which is not a biologically active compound, so producing companies must get rid of this compound by a complex purification process.Experiments done in this study were performed with the aim of improving the reaction using biocatalysts in mild conditions to solve the environment impact , and in order to obtain a 100% selective oxidizing agent avoiding the production of the undesired isomer, which is the key point for the success of this new process.The strains used in this work were mainly isolated from the environment, except for some of them which were purchased from international collections, and two of the wild strains, which were isolated from the substrate of the reaction, and three of the purchased strains showed a positive results for the produciton of vitamin K3 using 2-methylnaphtalene as substrate.The mechanism of the reaction involved the sequential oxidation of 2-methylnaphtalene to 2-methyl-1-naphtol and 2-methyl-4-naphtol, leading to Menadiol and finally leading to the formation of menadione as final product, with a 100% selective process for the production of quinones, avoiding the production of the undesired isomer.Different alternatives for the production of menadione were shown by using enzyme systems, active whole cells and whole resting cells of the 5 different menadione producing strains, from which the best results were achieved with Bacillus subtilis and Bacillus cereus biotype I resting cells in glucose.Molecular studies involving the cloning and expression of the cytochrome aa3 600 quinol oxidase of Bacillus subtilis in E.coli BL21, permitted us to determine that this protein is the responsible for the production of menadione using the substrate 2-methyl-1-naphtol, althoug no evidence of its activity against 2-methylnaphtalene was achieved.The results obtained in this work show a broad range of possibilities for alternative processes for the synthesis of vitamin K3, although this processes need to develope much further in order to compete with the stablished chemical process in terms of yield and production

  • Alternatives biotecnològiques a la síntesi química de la vitamina K3
    Bellaterra : Universitat Autònoma de Barcelona, 2004
    Co-Authors: Soldevila Fàbrega Andreu
    Abstract:

    Consultable des del TDXTítol obtingut de la portada digitalitzadaAquesta tesi tracta l'estudi de la producció de la vitamina K3 des d'un punt de vista biotecnològic amb l'objectiu de plantejar noves alternatives a la síntesis química clàssica d'aquesta vitamina. La síntesi clàssica de la vitamina K3 es realitza per un procediment químic que comporta una oxidació del 2-metilnaftalè com a material de partida, mitjançant un agent oxidant molt fort, el dicromat sòdic, en un medi que conté àcid sulfúric, creant-se una reacció que genera una elevadíssima quantitat de residus de crom en aigües àcides. Així doncs es tracta d'una reacció molt contaminant que alhora té unes limitacions des del punt de vista químic molt important, com és la no utilització d'un catalitzador, la generació de grans quantitats de residus, així com la formació d'un isòmer de la vitamina K3, la 6-metil-1,4-naftoquinona, de manera que es produeix un compost no biològicament actiu, del qual cal desfer-se mitjançant dificultosos processos de purificació. Els experiments realitzats en aquest treball van estar dirigits cap a la solució d'aquests problemes, és a dir, la utilització de biocatalitzadors en unes condicions suaus per a minimitzar l'impacte ambiental del procediment de síntesi , així com la millora de la selectivitat de la reacció, eliminantse la formació de l'isòmer de la vitamina K3, punt clau per a l'èxit d'aquest nou sistema de síntesi. Amb aquests objectius es va treballar amb microorganismes salvatges, així com amb microorganismes de col·leccions internacionals, fins que es va poder determinar que dos microorganismes salvatges aïllats del producte de partida de la reacció, el 2-metilnaftalè, així com tres soques de les col·leccions internacionals, eren capaços de produir vitamina K3 a partir d'aquest substracte. Un cop obtingudes les soques productores de vitamina K3 es va poder determinar el mecanisme de la reacció, que indicava la formació dels intermediaris 2-metil-1-naftol i 2-metil-4-naftol, seguit del Menadiol i finalment la formació de vitamina K3. També es va poder dur a terme la determinació de que els microorganismes productors de vitamina K3 tenien un 100% de selectivitat pel que fa a la formació de quinones, evitantse la formació de l'isòmer no desitjat, fet determinant per a l'interès del món químic-farmacèutic en una reacció d'aquest tipus. Es van poder mostrar diferents alternatives de síntesi d'aquesta vitamina utilitzant sistemes enzimàtics, cèl·lules senceres actives i cèl·lules senceres no proliferants, essent la producció amb Bacillus subtilis i Bacillus cereus biotip I en condicions de no proliferació en glucosa, les millor condicions de productivitat. Des del punt de vista dels estudis mol·leculars, es va poder determinar que la proteïna responsable de la síntesi de vitamina K3, utilitzant com a substracte el 2-metil-1-naftol, era la citocrom aa3-600quinol oxidasa de Bacillus subtilis , però no es va poder determinar la proteïna responsable del primer pas de la reacció, l'oxidació del 2-metilnaftalè a 2-metil-1-naftol. Els resultats obtinguts permeten veure un ventall de possibilitats que donen alternatives reals als processos clàssics de síntesi de la vitamina K3, tot i que són processos en els quals encara s'ha de treballar molt per augmentar-ne la productivitat fins a uns nivells òptims.The classical synthesis of vitamin K3 is done by a chemical process consisting of an oxidation of the substrate, 2-methylnaphtalene, with a powerful oxidizing agent such as sodium dichromate in a sulphuric acid medium, which leads to a stechiometric reaction that generates an extremely high amount of chromium waste in acidic waters. This process is extremely polluting and at the same time, from a chemical point of view, its limitations are very important. The most important limitations are the low atom echonomy, because no catalysis is achieved as it is a stechiometric reaction that produces a great amount of waste, and the production of an isomer(6-methyl-1,4-naphtoquinone) of the vitamin, which is not a biologically active compound, so producing companies must get rid of this compound by a complex purification process. Experiments done in this study were performed with the aim of improving the reaction using biocatalysts in mild conditions to solve the environment impact , and in order to obtain a 100% selective oxidizing agent avoiding the production of the undesired isomer, which is the key point for the success of this new process. The strains used in this work were mainly isolated from the environment, except for some of them which were purchased from international collections, and two of the wild strains, which were isolated from the substrate of the reaction, and three of the purchased strains showed a positive results for the produciton of vitamin K3 using 2-methylnaphtalene as substrate. The mechanism of the reaction involved the sequential oxidation of 2-methylnaphtalene to 2-methyl-1-naphtol and 2-methyl-4-naphtol, leading to Menadiol and finally leading to the formation of menadione as final product, with a 100% selective process for the production of quinones, avoiding the production of the undesired isomer. Different alternatives for the production of menadione were shown by using enzyme systems, active whole cells and whole resting cells of the 5 different menadione producing strains, from which the best results were achieved with Bacillus subtilis and Bacillus cereus biotype I resting cells in glucose. Molecular studies involving the cloning and expression of the cytochrome aa3 600 quinol oxidase of Bacillus subtilis in E.coli BL21, permitted us to determine that this protein is the responsible for the production of menadione using the substrate 2-methyl-1-naphtol, althoug no evidence of its activity against 2-methylnaphtalene was achieved. The results obtained in this work show a broad range of possibilities for alternative processes for the synthesis of vitamin K3, although this processes need to develope much further in order to compete with the stablished chemical process in terms of yield and production