Examinando por Materia "Bacteria"

Mostrando 1 - 12 de 12
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    Ítem
    Biodegradation of vegetable residues by polygalacturonase-agar using a trickle-bed bioreactor
    (Institution of Chemical Engineers, 2018-09-01) Ramírez-Tapias, Y.A.; Rivero, C.W.; Giraldo-Estrada, C.; Britos, C.N.; Trelles, J.A.; Universidad EAFIT. Departamento de Ciencias; Ciencias Biológicas y Bioprocesos (CIBIOP)
    Bacterial pectinases degrade the pectic substances present in plant tissues and particularly, polygalacturonases catalyze the hydrolysis of a-(1,4) glycosidic bonds linking D-galacturonic acid units. In this study, polygalacturonase from Streptomyces halstedii ATCC 10897 was immobilized by the matrix entrapment technique using different thermogels. Bacteriological agar added with magnesium cation produced beads with a more stabilized microstructure for enzyme retention, monitored by oscillatory measurements of storage and loss modulus. Agar concentration and protein content were optimized to maximize protein entrapment, product conversion, and reaction yield. Results showed that the mixture at 10:90% (v/v) of protein (2 mg/mL) and agar (4% w/v) was the best immobilization condition to retain 91% of protein and hydrolyze 38% of pectin to allow the highest reaction yield (9.279 g/g) and increase stability up to 48 h of successive reactions. Agarose bead biocatalysts were used in a trickle-bed column operated with recirculation, and this bioreactor allowed the degradation of pear and cucumber residues by enzymatic liquefaction to enhance sugar content up to 15.33 and 9.35 mg/mL, respectively, and decrease viscosity by 92.3%. The scale-up of this process adds value to vegetable residues such as fructooligosaccharides or fermentable sugars, which become a sustainable source of fuels and chemicals. © 2018 Institution of Chemical Engineers
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    Ítem
    ¿Cómo se vive en ambientes extremos?
    (2016-04-15) Pinel, Nicolás; González Cotes, Ana María; Arango Uribe, Ana María; Londoño Rivera, Ana María; Pinel, Nicolás; González Cotes, Ana María; Arango Uribe, Ana María; Londoño Rivera, Ana María
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    Ítem
    Determinación y evaluación de la microbiota intestinal común a la población colombiana
    (Universidad EAFIT, 2017) Valderrama Maya, Margarita María; Escobar Restrepo, Juan Sebastián; Pinel Peláez, Nicolás
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    Ítem
    Eliminación de coliformes totales y fecales de aguas crudas mediante electro-oxidación
    (Universidad EAFIT, 2016) Aljure Alvear, Isabelita; León Goméz, Susana; Gil Pavas, Edison Hernán
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    Enhanced molecular visualization of root colonization and growth promotion by Bacillus subtilis EA-CB0575 in different growth systems
    (Elsevier GmbH, 2018-01-01) Posada, L.F.; Álvarez, J.C.; Romero-Tabarez, M.; de-Bashan, L.; Villegas-Escobar, V.; Universidad EAFIT. Departamento de Ciencias; Ciencias Biológicas y Bioprocesos (CIBIOP)
    Bacillus subtilis EA-CB0575 is a plant growth-promoting bacterium (PGPB) associated with banana and tomato crops. Root colonization is an important trait for PGPB microorganisms and potentiates the bacterial effect related to the mechanisms of plant growth promotion. Therefore, detection of bacterial colonization of roots in different culture systems is important in the study of plant–microorganism interactions. In this study, fluorescent in situ hybridization (FISH) and catalyzed reporter deposition–FISH (CARD–FISH) were evaluated to determine the colonization ability of B. subtilis EA-CB0575 on banana and tomato roots planted on solid and liquid Murashige and Skoog medium (MS(S) and MS(L), respectively) and in soil for tomato plants. Results showed B. subtilis colonization 0–30 days post inoculation for banana and tomato plants in different culture systems with differential distribution of bacterial cells along tomato and banana roots. FISH and CARD–FISH methodologies were both successful in detecting B. subtilis colonies, but CARD–FISH proved to be superior due to its enhanced fluorescence signal. The presence of bacteria correlated with the promotion of plant growth in both plant species, providing clues to relate rhizospheric colonization with improvement in plant growth. FISH and CARD–FISH analysis results suggested the presence of native microbiota on the roots of in vitro banana plants, but not on those of tomato plants. © 2018 Elsevier GmbH
  • No hay miniatura disponible
    Ítem
    Enhanced molecular visualization of root colonization and growth promotion by Bacillus subtilis EA-CB0575 in different growth systems
    (Elsevier GmbH, 2018-01-01) Posada, L.F.; Álvarez, J.C.; Romero-Tabarez, M.; de-Bashan, L.; Villegas-Escobar, V.; Universidad EAFIT. Departamento de Ciencias; Biodiversidad, Evolución y Conservación
    Bacillus subtilis EA-CB0575 is a plant growth-promoting bacterium (PGPB) associated with banana and tomato crops. Root colonization is an important trait for PGPB microorganisms and potentiates the bacterial effect related to the mechanisms of plant growth promotion. Therefore, detection of bacterial colonization of roots in different culture systems is important in the study of plant–microorganism interactions. In this study, fluorescent in situ hybridization (FISH) and catalyzed reporter deposition–FISH (CARD–FISH) were evaluated to determine the colonization ability of B. subtilis EA-CB0575 on banana and tomato roots planted on solid and liquid Murashige and Skoog medium (MS(S) and MS(L), respectively) and in soil for tomato plants. Results showed B. subtilis colonization 0–30 days post inoculation for banana and tomato plants in different culture systems with differential distribution of bacterial cells along tomato and banana roots. FISH and CARD–FISH methodologies were both successful in detecting B. subtilis colonies, but CARD–FISH proved to be superior due to its enhanced fluorescence signal. The presence of bacteria correlated with the promotion of plant growth in both plant species, providing clues to relate rhizospheric colonization with improvement in plant growth. FISH and CARD–FISH analysis results suggested the presence of native microbiota on the roots of in vitro banana plants, but not on those of tomato plants. © 2018 Elsevier GmbH
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    Ítem
    Evolutionary and sequence-based relationships in bacterial AdoMet-dependent non-coding RNA methyltransferases
    (BioMed Central Ltd., 2014-01-01) Mosquera-Rendón, J.; Cárdenas-Brito, S.; Pineda, J.D.; Corredor, M.; Benítez-Páez, A.; Mosquera-Rendón, J.; Cárdenas-Brito, S.; Pineda, J.D.; Corredor, M.; Benítez-Páez, A.; Universidad EAFIT. Departamento de Ingeniería de Sistemas; I+D+I en Tecnologías de la Información y las Comunicaciones
    Background: RNA post-transcriptional modification is an exciting field of research that has evidenced this editing process as a sophisticated epigenetic mechanism to fine tune the ribosome function and to control gene expression. Although tRNA modifications seem to be more relevant for the ribosome function and cell physiology as a whole, some rRNA modifications have also been seen to play pivotal roles, essentially those located in central ribosome regions. RNA methylation at nucleobases and ribose moieties of nucleotides appear to frequently modulate its chemistry and structure. RNA methyltransferases comprise a superfamily of highly specialized enzymes that accomplish a wide variety of modifications. These enzymes exhibit a poor degree of sequence similarity in spite of using a common reaction cofactor and modifying the same substrate type. Results: Relationships and lineages of RNA methyltransferases have been extensively discussed, but no consensus has been reached. To shed light on this topic, we performed amino acid and codon-based sequence analyses to determine phylogenetic relationships and molecular evolution. We found that most Class I RNA MTases are evolutionarily related to protein and cofactor/vitamin biosynthesis methyltransferases. Additionally, we found that at least nine lineages explain the diversity of RNA MTases. We evidenced that RNA methyltransferases have high content of polar and positively charged amino acid, which coincides with the electrochemistry of their substrates. Conclusions: After studying almost 12,000 bacterial genomes and 2,000 patho-pangenomes, we revealed that molecular evolution of Class I methyltransferases matches the different rates of synonymous and non-synonymous substitutions along the coding region. Consequently, evolution on Class I methyltransferases selects against amino acid changes affecting the structure conformation. © 2014 Mosquera-Rendón et al.; licensee BioMed Central Ltd.
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    Novel smart dental composite with rechargeable antimicrobial capability
    (Society for Biomaterials, 2019-01-01) Londoño J.J.; Kosater W.; Correa S.; Orrego S.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Bioingeniería GIB (CES – EAFIT)
    Statement of Purpose: The most common cause of failure for dental restorations is secondary caries [1]. It results from bacterial colonization (e.g. Streptococcus mutans) at the interface between the implanted biomaterial and hard tissue. The bonding strength is degraded by bacterial acid production and cyclic stresses from mastication. Resin composites are currently the most widely used material for restorations due to their great aesthetics, strength, and ease of processing. However, resins present the highest failure rate [2] due to the increased accumulation of biofilms (increased acid production) compared to other restorative materials [3]. Recent studies have developed resin composites with antibacterial properties to mitigate acid production. However, the antimicrobial effects are vanished over time since the antibiofilm agents leach-out and no longer are capable to repel bacteria. In this work, we present a novel smart biomaterial with long-lasting antibiofilm capabilities with a single filler. The novel resin filler produces electrical charges that disrupt oral bacteria, (antimicrobial effect) and are activated by mastication. © 2019 Omnipress - All rights reserved.
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    Ítem
    Novel smart dental composite with rechargeable antimicrobial capability
    (Society for Biomaterials, 2019-01-01) Londoño J.J.; Kosater W.; Correa S.; Orrego S.
    Statement of Purpose: The most common cause of failure for dental restorations is secondary caries [1]. It results from bacterial colonization (e.g. Streptococcus mutans) at the interface between the implanted biomaterial and hard tissue. The bonding strength is degraded by bacterial acid production and cyclic stresses from mastication. Resin composites are currently the most widely used material for restorations due to their great aesthetics, strength, and ease of processing. However, resins present the highest failure rate [2] due to the increased accumulation of biofilms (increased acid production) compared to other restorative materials [3]. Recent studies have developed resin composites with antibacterial properties to mitigate acid production. However, the antimicrobial effects are vanished over time since the antibiofilm agents leach-out and no longer are capable to repel bacteria. In this work, we present a novel smart biomaterial with long-lasting antibiofilm capabilities with a single filler. The novel resin filler produces electrical charges that disrupt oral bacteria, (antimicrobial effect) and are activated by mastication. © 2019 Omnipress - All rights reserved.
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    Ítem
    Scale-up from shake flasks to pilot-scale production of the plant growth-promoting bacterium Azospirillum brasilense for preparing a liquid inoculant formulation
    (SPRINGER, 2013-11-01) Trujillo-Roldan, Mauricio A.; Valdez-Cruz, Norma A.; Gonzalez-Monterrubio, Cesar F.; Acevedo-Sanchez, Eduardo V.; Martinez-Salinas, Carlos; Garcia-Cabrera, Ramses I.; Gamboa-Suasnavart, Ramses A.; Marin-Palacio, Luz D.; Villegas, Jesus; Blancas-Cabrera, Abel; Trujillo-Roldan, Mauricio A.; Valdez-Cruz, Norma A.; Gonzalez-Monterrubio, Cesar F.; Acevedo-Sanchez, Eduardo V.; Martinez-Salinas, Carlos; Garcia-Cabrera, Ramses I.; Gamboa-Suasnavart, Ramses A.; Marin-Palacio, Luz D.; Villegas, Jesus; Blancas-Cabrera, Abel; Universidad EAFIT. Departamento de Ingeniería de Procesos; Procesos Ambientales (GIPAB)
    Azospirillum brasilense has industrial significance as a growth promoter in plants of commercial interest. However, there is no report in the literature disclosing a liquid product produced in pilot-scale bioreactors and is able to be stored at room temperature for more than 2 years. The aim of this work was to scale up a process from a shake flask to a 10-L lab-scale and 1,000-L pilot-scale bioreactor for the production of plant growth-promoting bacterium A. brasilense for a liquid inoculant formulation. Furthermore, this work aimed to determine the shelf life of the liquid formulation stored at room temperature and to increase maize crops yield in greenhouses. Under a constant oxygen mass transfer coefficient (K L a), a fermentation process was successfully scaled up from shake flasks to 10- and 1,000-L bioreactors. A concentration ranging from 3.5 to 7.5 × 108 CFU/mL was obtained in shake flasks and bioreactors, and after 2 years stored at room temperature, the liquid formulation showed one order of magnitude decrease. Applications of the cultured bacteria in maize yields resulted in increases of up to 95 % in corncobs and 70 % in aboveground biomass. © 2013 Springer-Verlag Berlin Heidelberg.
  • No hay miniatura disponible
    Ítem
    Scale-up from shake flasks to pilot-scale production of the plant growth-promoting bacterium Azospirillum brasilense for preparing a liquid inoculant formulation
    (SPRINGER, 2013-11-01) Trujillo-Roldan, Mauricio A.; Valdez-Cruz, Norma A.; Gonzalez-Monterrubio, Cesar F.; Acevedo-Sanchez, Eduardo V.; Martinez-Salinas, Carlos; Garcia-Cabrera, Ramses I.; Gamboa-Suasnavart, Ramses A.; Marin-Palacio, Luz D.; Villegas, Jesus; Blancas-Cabrera, Abel; Universidad EAFIT. Departamento de Ciencias; Ciencias Biológicas y Bioprocesos (CIBIOP)
    Azospirillum brasilense has industrial significance as a growth promoter in plants of commercial interest. However, there is no report in the literature disclosing a liquid product produced in pilot-scale bioreactors and is able to be stored at room temperature for more than 2 years. The aim of this work was to scale up a process from a shake flask to a 10-L lab-scale and 1,000-L pilot-scale bioreactor for the production of plant growth-promoting bacterium A. brasilense for a liquid inoculant formulation. Furthermore, this work aimed to determine the shelf life of the liquid formulation stored at room temperature and to increase maize crops yield in greenhouses. Under a constant oxygen mass transfer coefficient (K L a), a fermentation process was successfully scaled up from shake flasks to 10- and 1,000-L bioreactors. A concentration ranging from 3.5 to 7.5 × 108 CFU/mL was obtained in shake flasks and bioreactors, and after 2 years stored at room temperature, the liquid formulation showed one order of magnitude decrease. Applications of the cultured bacteria in maize yields resulted in increases of up to 95 % in corncobs and 70 % in aboveground biomass. © 2013 Springer-Verlag Berlin Heidelberg.
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    Ítem
    Solar and artificial UV inactivation of bacterial microbes by Ca-alginate immobilized TiO2 assisted by H2O2 using fluidized bed photoreactors
    (SCIENCE & TECHNOLOGY NETWORK INC, 2014-07-01) GilPavas, Edison; Acevedo, Jose; Lopez, Luis F.; Dobrosz-Gomez, Izabela; Angel Gomez-Garcia, Miguel; GilPavas, Edison; Acevedo, Jose; Lopez, Luis F.; Dobrosz-Gomez, Izabela; Angel Gomez-Garcia, Miguel; Universidad EAFIT. Departamento de Ingeniería de Procesos; Procesos Ambientales (GIPAB)
    In this work, TiO2 (Degussa, P-25) supported on calcium alginate pearls was evaluated as catalyst for the photocatalytic inhibition of pathogenic microorganisms. Considering that water samples were taken directly from a natural source, a primary treatment (coagulation, sedimentation and filtration) was executed to remove solids and impurities. Photocatalytic experiments were carried out in two types of laboratory scale equipments, one using an annular UV irradiated reactor and the other a solar UV parabolic collector, both operated in the fluidized bed mode. H2O2 was included to the reactive mixture in order to enhance the photodegradation rate. The Response Surface Methodology and the Box-Behnken experimental design techniques were applied as tools for the optimization of the operational conditions of the UV water purification system. Thus, the influence of UV radiation, TiO2 dose and H2O2 concentration on the faecal and total coliform percentage degradation were statistically analysed. The following optimal operational conditions were found: UV radiation = 310 nm, TiO2 dose = 0.2 g/L and H2O2 concentration = 30 mg/L. After water treatment at optimized conditions, total microorganism growing inhibition was observed. Additional experiments allowed proving the reusability of the immobilized catalyst. © 2014 Science & Technology Network, Inc.