Bioetanol de paja de trigo: estrategias de integración de las etapas de proceso

La presente Tesis Doctoral aborda el hecho de la integración de las etapas de proceso mediante el estudio de diferentes configuraciones para la producción de etanol a partir de paja de trigo. La producción máxima de etanol, así como los rendimientos y las productividades volumétricas han sido comparadas empleando diferentes estrategias de hidrólisis y fermentación separadas (HFS), sacarificación y fermentación simultáneas (SFS) y sacarificación y cofermentación simultáneas (SCFS) con diferentes cepas de levaduras etanologénicas: Saccharomyces cerevisiae Red Star, S. cerevisiae F12 y Kluyveromyces marxianus CECT 10875. Además, también se han llevado a cabo diferentes procesos de SFS y de SCFS en semicontinuo (con adición de sustrato por pulsos). La explosión por vapor ha sido la tecnología elegida para pretratar la paja de trigo ya que, da lugar a una alta recuperación de azúcares y a un aumento de la digestibilidad de la celulosa. Sin embargo, durante el pretratamiento también se produce la descomposición parcial de la hemicelulosa y a la generación de compuestos tóxicos, derivados de la degradación de los azúcares y la lignina, lo que puede afectar las siguentes etapas de hidrólisis y fermentación. Por ello, tras esta etapa se suele realizar la filtración del material pretratado con la consiguiente obtención de dos fracciones: una fracción sólida o residuo sólido insoluble (RSI) rica en celulosa y lignina y una fracción líquida o prehidrolizado rica en azúcares hemicelulósicos y productos inhibidores

Unraveling the potential of non-conventional yeasts in biotechnology.

Cost-effective microbial conversion processes of renewable feedstock into biofuels and biochemicals are of utmost importance for the establishment of a robust bioeconomy. Conventional baker's yeast Saccharomyces cerevisiae, widely employed in biotechnology for decades, lacks many of the desired traits for such bioprocesses like utilization of complex carbon sources or low tolerance towards challenging conditions. Many non-conventional yeasts (NCY) present these capabilities, and they are therefore forecasted to play key roles in future biotechnological production processes. For successful implementation of NCY in biotechnology, several challenges including generation of alternative carbon sources, development of tailored NCY and optimization of the fermentation conditions are crucial for maximizing bioproduct yields and titers. Addressing these challenges requires a multidisciplinary approach that is facilitated through the 'YEAST4BIO' COST action. YEAST4BIO fosters integrative investigations aimed at filling knowledge gaps and excelling research and innovation, which can improve biotechnological conversion processes from renewable resources to mitigate climate change and boost transition towards a circular bioeconomy. In this perspective, the main challenges and research efforts within YEAST4BIO are discussed, highlighting the importance of collaboration and knowledge exchange for progression in this research field

Production of Short-Chain Fatty Acids (Scfas) As Chemicals or Substrates for Microbes to Obtain Biochemicals

[Abstract] Carboxylic acids have become interesting platform molecules in the last years due to their versatility to act as carbon sources for different microorganisms or as precursors for the chemical industry. Among carboxylic acids, short-chain fatty acids (SCFAs) such as acetic, propionic, butyric, valeric, and caproic acids can be biotechnologically produced in an anaerobic fermentation process from lignocellulose or other organic wastes of agricultural, industrial, or municipal origin. The biosynthesis of SCFAs is advantageous compared to chemical synthesis, since the latter relies on fossil-derived raw materials, expensive and toxic catalysts and harsh process conditions. This review article gives an overview on biosynthesis of SCFAs from complex waste products. Different applications of SCFAs are explored and how these acids can be considered as a source of bioproducts, aiming at the development of a circular economy. The use of SCFAs as platform molecules requires adequate concentration and separation processes that are also addressed in this review. Various microorganisms such as bacteria or oleaginous yeasts can efficiently use SCFA mixtures derived from anaerobic fermentation, an attribute that can be exploited in microbial electrolytic cells or to produce biopolymers such as microbial oils or polyhydroxyalkanoates. Promising technologies for the microbial conversion of SCFAs into bioproducts are outlined with recent examples, highlighting SCFAs as interesting platform molecules for the development of future bioeconomy.This article is based upon work from COST Action Yeast4Bio (CA18229), supported by COST (European Cooperation in Science and Technology). Open access funding provided by Swedish University of Agricultural Sciences. CK, NOL, MCV from the BIOENGIN group, are grateful to Xunta de Galicia for its financial support to Competitive Reference Research Groups (ED431C 2021/55). They also thank the Spanish Ministry of Science and Innovation and European FEDER funding (PID2020-117805RB-I00) for financing ongoing research, at the BIOENGIN group, on the topic of this paper. ETP, CGF and SG acknowledge the projects BIOMIO + H2 (PID2020-119403RBC21) funded by MCIN/AEI/http://dx.doi.org/10.13039/501100011033 and OLEOFERM (EraBoBiotech; PCI2021-121936) funded by MCIN/AEI/http://dx.doi.org/10.13039/501100011033 and “European Union NextGenerationEU/PRTR”. ETP also acknowledges the grant RYC2019-027773-I funded by MCIN/AEI/http://dx.doi.org/10.13039/501100011033 and by “ESF Investing in your future”. VP and BM were supported by the Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning (Formas) [grant number 2018–01877]Xunta de Galicia; ED431C 2021/55Suecia. Research Council for Environment, Agricultural Sciences and Spatial Planning (Formas); 2018–0187

Metabolic engineering of Saccharomyces cerevisiae ethanol strains PE-2 and CAT-1 for efficient lignocellulosic fermentation

In this work, Saccharomyces cerevisiae strains PE-2 and CAT-1, commonly used in the Brazilian fuel ethanol industry, were engineered for xylose fermentation, where the first fermented xylose faster than the latter, but also produced considerable amounts of xylitol. An engineered PE-2 strain (MEC1121) efficiently consumed xylose in presence of inhibitors both in synthetic and corn-cob hydrolysates. Interestingly, the S. cerevisiae MEC1121 consumed xylose and glucose simultaneously, while a CEN.PK based strain consumed glucose and xylose sequentially. Deletion of the aldose reductase GRE3 lowered xylitol production to undetectable levels and increased xylose consumption rate which led to higher final ethanol concentrations. Fermentation of corn-cob hydrolysate using this strain, MEC1133, resulted in an ethanol yield of 0.47 g/g of total sugars which is 92% of the theoretical yield.This work was supported by the Fundacao para a Ciencia e Tecnologia (FCT) through projects RECI/BBB-EBI/0179/2012-FCOMP-01-0124-FEDER-027462, PEst-OE/EQB/LA0023/2013, "Bio-Ind - Biotechnology and Bioengineering for improved Industrial and Agro-Food processes, REF. NORTE-07-0124-FEDER-000028" Co-funded by the Programa Operacional Regional do Norte (ON.2 - O Novo Norte) QREN, FEDER, PTDC/AAC-AMB/120940/2010, EXPL/BBB-BIO/1772/2013 and the FEDER POFC-COMPETE (PEst-C/BIA/UI4050/2011). A.R. was supported by FCT fellowship [SFRH/BPD/77995/2011] and F.P. by FCT fellowships [SFRH/BD/80934/2011 and SFRH/BD/42565/2007]

Obstetric–Neonatal Care during Birth and Postpartum in Symptomatic and Asymptomatic Women Infected with SARS-CoV-2: A Retrospective Multicenter Study

Data Availability Statement: Data are available upon reasonable request. All necessary data are supplied and available in the manuscript; however, the corresponding author will provide the dataset upon request. All data relevant to the study are included in the article.Copyright © 2022 by the authors. This study analyses the obstetric–neonatal outcomes of women in labour with symptomatic and asymptomatic COVID-19. A retrospective, multicenter, observational study was carried out between 1 March 2020 and 28 February 2021 in eight public hospitals in the Valencian community (Spain). The chi-squared test compared the obstetric–neonatal outcomes and general care for symptomatic and asymptomatic women. In total, 11,883 births were assisted in participating centers, with 10.9 per 1000 maternities (n = 130) infected with SARS-CoV-2. The 20.8% were symptomatic and had more complications both upon admission (p = 0.042) and during puerperium (p = 0.042), as well as transfer to the intensive care unit (ICU). The percentage of admission to the Neonatal Intensive Care Unit (NICU) was greater among offspring of symptomatic women compared to infants born of asymptomatic women (p < 0.001). Compared with asymptomatic women, those with symptoms underwent less labour companionship (p = 0.028), less early skin-to-skin contact (p = 0.029) and greater mother–infant separation (p = 0.005). The overall maternal mortality rate was 0.8%. No vertical transmission was recorded. In conclusion, symptomatic infected women are at increased risk of lack of labour companionship, mother–infant separation, and admission to the ICU, as well as to have preterm births and for NICU admissions.FISABIO grant number UGP-20-24

Obstetric–neonatal care during birth and postpartum in symptomatic and asymptomatic women infected with SARS-CoV-2: a retrospective multicenter study

This study analyses the obstetric–neonatal outcomes of women in labour with symptomatic and asymptomatic COVID-19. A retrospective, multicenter, observational study was carried out between 1 March 2020 and 28 February 2021 in eight public hospitals in the Valencian community (Spain). The chi-squared test compared the obstetric–neonatal outcomes and general care for symptomatic and asymptomatic women. In total, 11,883 births were assisted in participating centers, with 10.9 per 1000 maternities (n = 130) infected with SARS-CoV-2. The 20.8% were symptomatic and had more complications both upon admission (p = 0.042) and during puerperium (p = 0.042), as well as transfer to the intensive care unit (ICU). The percentage of admission to the Neonatal Intensive Care Unit (NICU) was greater among offspring of symptomatic women compared to infants born of asymptomatic women (p < 0.001). Compared with asymptomatic women, those with symptoms underwent less labour companionship (p = 0.028), less early skin-to-skin contact (p = 0.029) and greater mother–infant separation (p = 0.005). The overall maternal mortality rate was 0.8%. No vertical transmission was recorded. In conclusion, symptomatic infected women are at increased risk of lack of labour companionship, mother–infant separation, and admission to the ICU, as well as to have preterm births and for NICU admissions

Hybridization and adaptive evolution of diverse Saccharomyces species for cellulosic biofuel production

Additional file 15. Summary of whole genome sequencing statistics