Producción de aromáticos por despolimerización reductiva de lignina sobre catalizadores carbonosos producidos a partir de lignosulfonato sódico.

El incremento de la producción de lignina en la industria de la producción de pasta de celulosa y en las biorefinerías lignocelulósicas, junto con la creciente demanda de procesos con cero producción de residuos en el marco de la bioeconomía circular, hace necesario desarrollar nuevas metodologías para la valorización de la lignina. Este trabajo propone su doble valorización mediante su conversión en catalizadores basados en carbono y la aplicación de éstos en su despolimerización reductiva para la producción de monómeros aromáticos de alto valor añadido. Los carbones activados empleados como soporte catalítico fueron preparados por activación química de un lignosulfonato de sodio con H3PO4 en relación 3/1 (masa agente activante/precursor carbonoso) y activados a 500 °C. El carbón activado fue impregnado con distintas cantidades de sales precursoras de níquel, molibdeno y cobalto y sometido a tratamiento térmico a 800 °C, produciendo un catalizador de níquel y dos catalizadores bimetálicos de Ni-Mo, y Co-Mo. La despolimerización reductiva de lignina organosolv se llevó a cabo empleando estos catalizadores en un reactor discontinuo agitado a 350 °C y 100 bar de presión inicial de H2 durante 4 horas. En todas las reacciones se obtuvo una fase gaseosa, una líquida orgánica, una líquida acuosa y una sólida, las cuales fueron caracterizadas a través de diferentes técnicas. El catalizador carbonoso con Ni y Mo fue el más activo, despolimerizando en gran medida la lignina, y mostrando una moderada actividad en la hidrodesoxigenación de los correspondientes monoméros aromáticos en condiciones suaves. La fase líquida orgánica obtenida presentó un alto rendimiento hacia los monoméros y elevada selectividad hacia aromáticos oxigenados de alto valor económico, como los alquilfenoles. Además, en las pruebas de reacción utilizando como materia prima otra lignina de alto contenido de azufre, el catalizador mantuvo su actividad.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

The Pleiotropic CymR Regulator of Staphylococcus aureus Plays an Important Role in Virulence and Stress Response

We have characterized a novel pleiotropic role for CymR, the master regulator of cysteine metabolism. We show here that CymR plays an important role both in stress response and virulence of Staphylococcus aureus. Genes involved in detoxification processes, including oxidative stress response and metal ion homeostasis, were differentially expressed in a ΔcymR mutant. Deletion of cymR resulted in increased sensitivity to hydrogen peroxide-, disulfide-, tellurite- and copper-induced stresses. Estimation of metabolite pools suggests that this heightened sensitivity could be the result of profound metabolic changes in the ΔcymR mutant, with an increase in the intracellular cysteine pool and hydrogen sulfide formation. Since resistance to oxidative stress within the host organism is important for pathogen survival, we investigated the role of CymR during the infectious process. Our results indicate that the deletion of cymR promotes survival of S. aureus inside macrophages, whereas virulence of the ΔcymR mutant is highly impaired in mice. These data indicate that CymR plays a major role in virulence and adaptation of S. aureus for survival within the host

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Preparation of Lignosulfonate-Based Carbon Foams by Pyrolysis and Their Use in the Microencapsulation of a Phase Change Material

International audienceCurrently, further research on the valorization of lignin is needed to shift biorefineries from a conceptual basis to profitable practice. Providing global warming is a major concern as well, the use of lignin as the sole precursor to elaborate materials with thermal energy storage (TES) applications is especially welcomed in the search for new sustainable solutions. To this end, the preparation of on demand macroporous carbon foams from calcium lignosulfonate (CaLS) by pyrolysis is described herein, and their capability to microencapsulate phase change materials (PCMs) dedicated to the passive refrigeration of buildings by TES is further assessed as a proof of concept. The as-produced CaLS-based foams were found to be efficient containers for this purpose, displaying any appreciable leakage of PCMs. Furthermore, the thermal properties of the final materials were satisfactory as well, showing that the support does not affect the PCM performance negatively. Considering the process to produce such materials is not only straightforward but also relies on an inexpensive, widely available carbon precursor, it is expected that it serves as a starting point for pilot studies in TES projects

Phage lambda cDNA cloning vectors for subtractive hybridization, fusion-protein synthesis and Cre-loxP automatic plasmid subcloning

We describe the construction and use of two classes of cDNA cloning vectors. The first class comprises the ΛEXLX(+) and λEXLX(−) vectors that can be used for the expression in Escherichia coli of protein encoded by cDNA inserts is achived by the fusion of cDNA open reading frames to the T7 gene 10 promoter and protein-coding sequences. The second class, the λSHLX vectors, allows the generation of large amounts of single-stranded DNA or synthetic cRNA that can be used in subtractive hybridization procedures. Both classes of vectors are designed to allow directional cDNA cloning with non-enzymatic protection of internal restriction sites. In addition, they are designed to facilitate conversion from phage λ to plasmid clones using a genetic method based on the bacteriophage P1 site-specific recombination system; we refer to this as automatic Cre-loxP plasmid subcloning. The phage λ arms, λLOX, used in the construction of these vectors have unique restriction sites positioned between the two loxP sites. Insertion of specialized plasmid between these items sites will convert it into a phage λ cDNA cloning vector with automatic plasmid subcloning capability

Complete sequence of the bithorax complex of Drosophila.

The bithorax complex (BX-C) of Drosophila, one of two complexes that act as master regulators of the body plan of the fly, is included within a sequence of 338,234 bp (SEQ89E). This paper presents the strategy used in sequencing SEQ89E and an analysis of its open reading frames. The BX-C sequence (BXCALL) contains 314,895 bp obtained by deletion of putative genes that are located at each end of SEQ89E and appear to be functionally unrelated to the BX-C. Only 1.4% of BXCALL codes for the three homeodomain-containing proteins of the complex. Principal findings include a putative ABD-A protein (ABD-AII) larger than a previously known ABD-A protein and a putative glucose transporter-like gene (1521 bp) located at or near the bithoraxoid (bxd), infra-abdominal-2 (iab-2) boundary on the opposite strand relative to that of the homeobox-containing genes