Potencial biotecnológico para la valorización de residuos generados en granjas porcinas y cultivos de trigo

Objetivo: identificar las biotecnologías disponibles para valorizar y tratar los residuos generados en granjas de cerdos y cultivos de trigo. Método: revisión de literatura científica y reportes gubernamentales para recopilar la información y datos presentados. Resultados: identificación de procesos novedosos que aplican biotecnología para la obtención de productos de valor actual a partir de residuos de paja de trigo y agua residual porcina. Limitaciones: se centra en procesos microbiológicos para la valorización de los residuos. Principales hallazgos: se propone la aplicación de procesos que permiten la generación de energía por medios alternos y la producción de compuestos químicos de valor, aunado a la disminución de desechos que entran al ambiente

A Theoretical Study of the Hydration of Methane, from the Aqueous Solution to the sI Hydrate-Liquid Water-Gas Coexistence

Monte Carlo and molecular dynamics simulations were done with three recent water models TIP4P/2005 (Transferable Intermolecular Potential with 4 Points/2005), TIP4P/Ice (Transferable Intermolecular Potential with 4 Points/ Ice) and TIP4Q (Transferable Intermolecular Potential with 4 charges) combined with two models for methane: an all-atom one OPLS-AA (Optimal Parametrization for the Liquid State) and a united-atom one (UA); a correction for the C–O interaction was applied to the latter and used in a third set of simulations. The models were validated by comparison to experimental values of the free energy of hydration at 280, 300, 330 and 370 K, all under a pressure of 1 bar, and to the experimental radial distribution functions at 277, 283 and 291 K, under a pressure of 145 bar. Regardless of the combination rules used for σC,O, good agreement was found, except when the correction to the UA model was applied. Thus, further simulations of the sI hydrate were performed with the united-atom model to compare the thermal expansivity to the experiment. A final set of simulations was done with the UA methane model and the three water models, to study the sI hydrate-liquid water-gas coexistence at 80, 230 and 400 bar. The melting temperatures were compared to the experimental values. The results show the need to perform simulations with various different models to attain a reliable and robust molecular image of the systems of interest

Phenol and methylene blue adsorption on heat-treated activated carbon: Characterization, kinetics, and equilibrium studies

A comprehensive study was performed for a thermally treated activated carbon to evaluate the influence of this treatment on the physical and chemical properties of the mineral activated carbon, as well as the adsorption toward phenol and methylene blue. After the heat treatment, surface area decreased and total pore volume diminished about 8.5%, and the total basic groups decreased 18% while the total acid groups increased 8% in comparison with the raw activated carbon. Equilibrium adsorption of phenol and methylene blue was described well with the Freundlich and Langmuir isotherm models, respectively. Adsorption kinetics of phenol and methylene blue was predicted adequately with the empirical pseudo-second-order model, the intraparticle diffusion model, and the homogeneous solid diffusion model, but mass transfer coefficients of the diffusion models help to better understand the adsorption phenomenon. Intraparticle diffusion seems to be the rate-controlling step in the adsorption process, and heat-treated activated carbon in an inert atmosphere was a better adsorbent for both phenol and methylene blue than raw activated carbon

Globulin 11S and Its Mixture with l-DPPC at the Air/Liquid Interface

"Langmuir films of globulin 11S protein, L-dipalmitoylphosphatidylcholine (L-DPPC), and mixtures of both on water and on buffer subphases were studied. Brewster angle microscopy (BAM) was used to characterize in situ the films morphology along Pi-A isotherms at the air/liquid interface. The L-DPPC monolayer on water behaved as has been reported extensively in the literature but a slight increase on surface pressure and a notable change in domain morphology is observed on buffer. This difference in domain behavior is due to the stabilization interaction of the LE phase by the buffer ions. On the other hand, the protein monolayer was prepared by direct deposit or injection below the surface. Both methods formed mostly a condensed film, with a multilayer formed by globular aggregates in the first method with the two subphases. However, the second method showed different behavior of the protein films depending on the subphase; on water the protein formed a homogeneous film with some globule aggregates, but on buffer a remarkably well-organized monolayer was observed by atomic force microscopy (AFM). Mixtures of globulin 11S and L-DPPC were prepared using both methods for the protein film formation at the air/fluid interface. BAM showed that the mixtures formed coexistence regions between two condensed phases, whose domains of both phases behave like liquids. Fingering phenomena were observed at the interface between protein-rich and L-DPPC-rich domains, which indicates that both phases are fluid. AFM images of the Mixtures show the formation of protein- or L-DPPC-rich domains. The liquidlike behavior could be explained due to different sizes of the protein and the L-DPPC, the minority compound in each kind of domain produces defects making them behave as liquids. Interestingly enough, as the monolayer is compressed to higher surface pressure, the lipid molecules are squeezed out and complete separation of the protein and L-DPPC is produced, Furthermore, we present evidence that the protein/L-DPPC mixtures produce films with holes, which might indicate its tendency to form hollow aggregates that could have some relevance in water-channel formation for in vivo seed germination.