Producción de 2,3-butanodiol a partir de glicerina (residuo de biodiésel)

Desde hace más de una década, la Unión Europea, a través de un marco legislativo, ha apostado por el desarrollo de la industria del biodiesel como alternativa sostenible al empleo de combustibles fósiles en el sector de los transportes. Como subproducto del proceso se genera glicerina en, aproximadamente, un 10% en masa respecto al biodiesel producido. Debido a la consecuente saturación del mercado de la glicerina, es necesaria la búsqueda de nuevas vías de revalorización de este residuo, con el fin de potenciar la integración en la biorrefinería y mejorar su rentabilidad económica. La presente Tesis Doctoral “Producción de 2,3-butanodiol a partir de glicerina (residuo del biodiesel)” profundiza en la revalorización biotecnológica del residuo para producir un compuesto de mayor valor añadido, el 2,3-butanodiol. Hasta el momento, este bioproceso ha sido escasamente estudiado, hecho que pone de manifiesto la justificación de esta investigación. La metodología empleada para el desarrollo del bioproceso comprende diferentes etapas, descritas a continuación..

Kinetic modelling of anaerobic co-digestion of sewage sludge and Sherry-wine distillery wastewater: Effect of substrate composition in batch bioreactor.

Batch thermophilic anaerobic co-digestion of sewage sludge (SS) and Sherry-wine distillery wastewater (SW-DW) was investigated through biochemical methane potential tests (BMP). The results pointed out that biodegradability and biomethane potential were enhanced proportionally to the percentage of SW-DW of the feedstock, whose soluble biodegradability fraction is 10-fold higher than SS. Specifically, organic matter removal increases from 37 % (employing sole SS as feedstock) to 60 % (employing sole SW-DW as feedstock). SW-DW almost doubles methane yield in comparison to SS (302 ± 15 and 175 ± 9 NL/kg, respectively). A structured kinetic model was developed considering hydrolysis, acidogenic and methanogenic steps of anaerobic digestion. A non-linear multiple-response regression was employed to estimate the kinetic parameters for each feedstock (0%(v/v) SW-DW, 25%(v/v) SW-DW, 50%(v/v) SW-DW, 75%(v/v) SW-DW, and 100%(v/v) SW-DW). The first-order kinetic parameter estimated of the hydrolysis step varies inversely proportional to the percentage of SW-DW content in the feedstock. Whereas, there is no significant influence of feedstock composition on kinetic parameters value regarding acidogenesis and methanogenesis. These results showed that rate–limiting step switched during the fermentation and the addition of SW–DW favours acidogenic and methanogenic steps. In summary, the proposed kinetic model was able to predict batch experimental data, supporting the application of biogas production from anaerobic co-digestion of SS and DW-DW.post-print703 K

High 2,3-butanediol production from glycerol by Raoultella terrigena CECT 4519.

Bioconversion of biodiesel-derived glycerol into 2,3-butanediol has received recently much attention due to its increasing surplus and its multiple uses in industry as bulk chemical. The influence of initial glycerol concentration on 2,3-butanediol production in batch runs has been studied. A concentration higher than 140 g/L produces an inhibitory effect on the final 2,3-butanediol concentration and its production rate. In batch mode, the highest yield respect to the theoretical maximum yield (71%) was reached employing 140 g/L as initial concentration 140 g/L. Based on these results, a high 2,3-butanediol production has been achieved through a fed-batch strategy. The reached 2,3-butanediol concentration was 90.5 g/L from pure glycerol and 80.5 g/L from raw glycerol. The 2,3-butanediol yield respect to the theoretical maximum yield was also improved through the fed-batch operation (90%). To date, this concentration is the highest produced amount employing as biocatalyst a non-pathogenic bacterium (level 1).pre-print478 K

Kinetic modelling of anaerobic co-digestion of sewage sludge and Sherry-wine distillery wastewater: Effect of substrate composition in batch bioreactor

Batch thermophilic anaerobic co-digestion of sewage sludge (SS) and Sherry-wine distillery wastewater (SW-DW) was investigated through biochemical methane potential tests (BMP). The results pointed out that biodegrad-ability and biomethane potential were enhanced proportionally to the percentage of SW-DW of the feedstock, whose soluble biodegradability fraction is 10-fold higher than SS. Specifically, organic matter removal increases from 37 % (employing sole SS as feedstock) to 60 % (employing sole SW-DW as feedstock). SW-DW almost doubles methane yield in comparison to SS (302 +/- 15 and 175 +/- 9 NL/kg, respectively). A structured kinetic model was developed considering hydrolysis, acidogenic and methanogenic steps of anaerobic digestion. A non-linear multiple-response regression was employed to estimate the kinetic parameters for each feedstock (0%(v/v) SW-DW, 25%(v/v) SW-DW, 50%(v/v) SW-DW, 75%(v/v) SW-DW, and 100%(v/v) SW-DW). The first-order kinetic parameter estimated of the hydrolysis step varies inversely proportional to the percentage of SW-DW content in the feedstock. Whereas, there is no significant influence of feedstock compo-sition on kinetic parameters value regarding acidogenesis and methanogenesis. These results showed that rate-limiting step switched during the fermentation and the addition of SW-DW favours acidogenic and meth-anogenic steps. In summary, the proposed kinetic model was able to predict batch experimental data, supporting the application of biogas production from anaerobic co-digestion of SS and DW-DW

Multiancestry analysis of the HLA locus in Alzheimer’s and Parkinson’s diseases uncovers a shared adaptive immune response mediated by HLA-DRB1*04 subtypes

Across multiancestry groups, we analyzed Human Leukocyte Antigen (HLA) associations in over 176,000 individuals with Parkinson’s disease (PD) and Alzheimer’s disease (AD) versus controls. We demonstrate that the two diseases share the same protective association at the HLA locus. HLA-specific fine-mapping showed that hierarchical protective effects of HLA-DRB1*04 subtypes best accounted for the association, strongest with HLA-DRB1*04:04 and HLA-DRB1*04:07, and intermediary with HLA-DRB1*04:01 and HLA-DRB1*04:03. The same signal was associated with decreased neurofibrillary tangles in postmortem brains and was associated with reduced tau levels in cerebrospinal fluid and to a lower extent with increased Aβ42. Protective HLA-DRB1*04 subtypes strongly bound the aggregation-prone tau PHF6 sequence, however only when acetylated at a lysine (K311), a common posttranslational modification central to tau aggregation. An HLA-DRB1*04-mediated adaptive immune response decreases PD and AD risks, potentially by acting against tau, offering the possibility of therapeutic avenues

1,3-Propanediol production by Klebsiella oxytoca NRRL-B199 from glycerol. Medium composition and operational conditions

Production of 1,3-propanediol from glycerol using Klebsiella oxytoca NRRL-B199 has been studied. Medium composition has been optimized by means of a statistical design based on the Taguchi method. Strong influences of glycerol and phosphate concentrations have been detected on biomass and product yields. Other factors, such as magnesium concentration and K:Na ratio, have shown a small influence on both responses, biomass and product concentrations. An optimized medium composition has been proposed, leading to a final 1,3-propanediol concentration of 12.4 g/L with a selectivity of 72% with respect to glycerol consumed at shaken bottle-scale. Once the medium composition had been optimized, the scale-up from shaken bottles to STBR was conducted. Several experiments in a 2 L STBR have been conducted in order to determine the best operating conditions concerning temperature and agitation. Under the best operating conditions, i.e., a programmed variable stirring rate ranging from 50 to 100 rpm and a temperature of 37 �C, a final concentration of 13.5 g/L of 1,3-propanediol with a selectivity of 86% with respect to the glycerol consumed was obtained

Innovation tools for Chem-E-Car Competition in Spain

Desarrollo de herramientas docentes para la adquisición de la capacidad de controlar de forma segura una reacción química, concibiendo, diseñando y ejecutando un sistema cumpliendo los estándares de seguridad y medioambientales. Las herramientas desarrolladas son de aplicación a un posible implantación de la competición desarrollada por AIChE: "Chem-E-Car".Development of teaching tools to acquire the ability to safely control a chemical reaction, conceiving, designing and implementing a system meeting the safety and environmental standards. The tools developed are designed for a possible implementation of the competition developed by AIChE, "Chem-E-Car".Depto. de Ingeniería Química y de MaterialesFac. de Ciencias QuímicasFALSEsubmitte

New insights into the genetic etiology of Alzheimer’s disease and related dementias

Characterization of the genetic landscape of Alzheimer’s disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/‘proxy’ AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele