Examinando por Autor "Bautista, L.F."

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Assessment of the efficiency of in situ bioremediation techniques in a creosote polluted soil: change in bacterial community.
(ELSEVIER, 2013) Simarro, R; González, N.; Bautista, L.F.; Molina, M.C.
This work aimed to assess the effectiveness of different in situ bioremediation treatments (bioaugmentation, biostimulation, bioaugmentation and biostimulation, and natural attenuation) on creosote polluted soil. Toxicity, microbial respiration, creosote degradation and the evolution of bacterial communities were analyzed. Results showed that creosote decreased significantly in all treatments, and no significant differences were found between treatments. However, some specific polycyclic aromatic hydrocarbons (PAH) were degraded to a greater extent by biostimulation. The dominance of low temperatures (8.9ºC average) slowed down microbial creosote and PAH uptake and, despite significantly creosote degradation (>60%) at the end of the experiment, toxicity remained constant and high throughout the biodegradation process. DGGE results revealed that biostimulation showed the highest microbial biodiversity, although at the end of the biodegradation process, community composition in all treatments was different from that of the control assay (unpolluted soil). The active uncultured bacteria belonged to the genera Pseudomonas, Sphingomonas, Flexibacter, Pantoea and Balneimonas, the latter two of which have not been previously described as PAH degraders. The majority of the species identified during the creosote biodegradation belonged to Pseudomonas genus, which has been widely studied in bioremediation processes. Results confirmed that some bacteria have an intrinsic capacity to degrade the creosote without previous exposure.
Effect of surfactants on PAH biodegradation by a bacterial consortium and on the dynamics of the bacterial community during the process
(ELSEVIER, 2011) González, N.; Simarro, R.; Molina, M.C.; Bautista, L.F.; Delgado, L.; Villa, J.A.
The aim of this work was to evaluate the effect of a non-biodegradable (Tergitol NP-10) and a biodegradable (Tween-80) surfactant on growth, degradation rate and microbial dynamics of a polycyclic aromatic hydrocarbon (PAHs) degrading consortium (C2PL05) from a petroleum polluted soil, applying cultivable and non cultivable techniques. Growth and degradation rate were significantly lower with Tergitol NP-10 than that with Tween-80. Toxicity did not show any significant reduction with Tergitol NP-10 whereas with Tween-80 toxicity was almost depleted (30%) after 40 days. Regarding to the cultured bacteria, Pseudomonas and Stenotrophomonas groups were dominant during PAH degradation with Tergitol NP-10, whereas Enterobacter and Stenotrophomonas were dominant with Tween-80. DGGE analyses (PRIMER and MDS) showed that bacteria composition was more similar between treatments when PAHs were consumed than when PAHs concentration was still high. Community changes between treatments were a consequence of Pseudomonas sp., Sphingomonas sp., Sphingobium sp. and Agromonas sp.
Modelling the adsorption and controlled release of drugs from the pure and amino surface-functionalized mesoporous silica hosts
(Elsevier, 2018-05-15) Martín, A.; Morales, V.; Ortiz-Bustos, J.; Pérez-Garnés, M.; Bautista, L.F.; García-Muñoz, R.A.
Several mesoporous silica materials with different structures were investigated as matrices for controlled drug delivery. The aim of this study is correlating the textural and surface chemical properties of these materials with the adsorption and delivery of the drug model methylprednisolone sodium succinate. The materials were synthesized according to different protocols, and employing both cationic and non-ionic surfactants. Additionally, the functionalization of the materials' surface with 1-[3-(trimethoxysilyl)propyl]diethylenetriamine (DT) was accomplished to study the synergistic effect of the incorporation of amine groups and textural properties on the loading and delivery of drug. The thermodynamics and dynamic adsorption behavior of these materials were determined and fitted to several isotherms models to provide information about the drug adsorption processes. The maximum adsorption capacities of the raw silica supports were correlated with the pore size and the results indicated that the drug adsorption ability improved as the material pore size increases. Moreover, it is observed that the drug adsorption on materials with mesoporous size higher than 10 nm are very close to the theoretical saturation capacity. Regarding amino-modified materials, isotherms models confirmed that the factor governing the adsorption process were mainly the electrostatic interactions, hydrogen bonding and/or hydrophobic-hydrophilic interactions between the drug moieties and amino-functionalized silica surfaces, and in a lesser degree the textural properties of the support. Furthermore, the kinetics of the drug release from these materials functionalized with amino groups were also modelled to finally obtain a correlation between the adsorption and release drug cargo from the host pure and surface-functionalized materials.
Zr-SBA-15 Acid Catalyst: Optimization of the Synthesis and Reaction Conditions for Biodiesel Production from Low-grade Oils and Fats
(Elsevier, 2012-11) Melero, J.A.; Bautista, L.F.; Iglesias, J.; Morales, G.; Sánchez-Vázquez, R.
The production of biodiesel by methanolysis of highly acidic crude palm oil has been optimized for the Zr-SBA-15 heterogeneous acid catalyst. A dual optimization procedure has been carried out using surface response methodology and selecting the yield towards fatty acid methyl esters (FAMEs) as main response factor. Selected target variables for the optimization were: acidity of the synthesis media, zirconium loading, ageing temperature (all three for the synthesis of the catalyst); and temperature, methanol to oil molar ratio, catalyst loading (for the reaction tests). Quadratic equations were obtained for both models and their statistical analysis led to the optimal conditions for Zr-SBA-15 synthesis (0.67 N HCl media concentration, 130ºC ageing temperature, 10 Si/Zr molar ratio), and for the transesterification reaction conditions (209ºC, 12.45 wt% catalyst loading, 45.8 methanol to oil molar ratio). Under these optimized conditions FAME yield reached 92 mol% after 6 h. Additionally, reusability tests revealed that the optimized Zr-SBA-15 catalyst displays an excellent reaction stability, being fully regenerated after calcination at 450ºC. Moreover, the high catalytic activity and stability achieved with crude palm oil is retained when using waste cooking oil (WCO) or low-grade fats such as category-1 fat, waste lard and mixed fats, leading to FAME yields over 90% after 6 hours, for each raw material, and with acidities in the final product lower than 2.5 mg KOH per gram.