44 research outputs found

    Single cell oil production by oleaginous yeasts grown in synthetic and waste-derived volatile fatty acids

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    Four yeast isolates from the species—Apiotrichum brassicae, Candida tropicalis, Metschnikowia pulcherrima, and Pichia kudriavzevii—previously selected by their oleaginous character and growth flexibility in different carbon sources, were tested for their capacity to convert volatile fatty acids into lipids, in the form of single cell oils. Growth, lipid yields, volatile fatty acids consumption, and long-chain fatty acid profiles were evaluated in media supplemented with seven different volatile fatty acids (acetic, butyric, propionic, isobutyric, valeric, isovaleric, and caproic), and also in a dark fermentation effluent filtrate. Yeasts A. brassicae and P. kudriavzevii attained lipid productivities of more than 40% (w/w), mainly composed of oleic (>40%), palmitic (20%), and stearic (20%) acids, both in synthetic media and in the waste-derived effluent filtrate. These isolates may be potential candidates for single cell oil production in larger scale applications by using alternative carbon sources, combining economic and environmental benefits.This work was supported by the European project "VOLATILE-Biowaste derived volatile fatty acid platform for biopolymers, bioactive compounds and chemical building blocks" (Call H2020-NMBP-BIO-2016 Grant agreement No. 720777) and by the strategic programme UID/BIA/04050/2013 (POCI-01-0145-FEDER-007569) funded by national funds through the FCT I.P., by the ERDF through the COMPETE2020

    World state of quality: a frontier approach to benchmark the performance of countries worldwide

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    Purpose - The World State of Quality (WSQ) Project aims to evaluate, analyse, rank and categorise countries according to their performance in quality as a multidimensional concept. The Project involves the computation of an overall score for each country, obtained as a weighted average of ranking positions of 16 metrics, with weights determined by a panel of experts. Methodology-This work proposes an alternative strategy for that procedure, using a Benefit-of-the-Doubt (BoD) Composite Indicator approach under the framework of Data Envelopment Analysis (DEA). This strategy avoids the need of using subjective weights and normalising data by rank positions, using a more objective procedure to obtain the countries’ ranking. A new overall score of the World State of Quality is proposed, which allows the categorisation of countries’ performance. The novel insights resulting from the use of this methodology are discussed, including the identification of strengths and weaknesses of the various countries, and the peers that can be used for facilitating continuous improvements policies. Findings - The results show that the BoD approach and the original method used by the WSQ Project present comparable results. Countries’ strengths and weaknesses and their suitable peers and targets for benchmarking are presented with illustrative examples. Originality/value – A novel frontier approach for countries’ benchmarking regarding their performance in quality is proposed, incorporating new insights into the current method.FCT - Fundação para a Ciência e a Tecnologia(2021.05244)The authors acknowledge the financial support provided by FCT- Fundação para a Ciência e a Tecnologia (Portuguese National Funding Agency for Science, Research and Technology) through PhD research grants and SFRH/BD/131285/2017. This work has been supported by FCT – Fundação para a Ciência e Tecnologia within the R&D Units Project Scope: UIDB/00319/2020

    Modified high-throughput Nile red fluorescence assay for the rapid screening of oleaginous yeasts using acetic acid as carbon source

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    Background: Over the last years oleaginous yeasts have been studied for several energetic, oleochemical, medical and pharmaceutical purposes. However, only a small number of yeasts are known and have been deeply exploited. The search for new isolates with high oleaginous capacity becomes imperative, as well as the use of alternative and ecological carbon sources for yeast growth. Results: In the present study a high-throughput screening comprising 366 distinct yeast isolates was performed by applying an optimised protocol based on two approaches: (I) yeast cultivation on solid medium using acetic acid as carbon source, (II) neutral lipid estimation by fluorimetry using the lipophilic dye Nile red. Conclusions: Results showed that, with the proposed methodology, the oleaginous potential of yeasts with broad taxonomic diversity and variety of growth characteristics was discriminated. Furthermore, this work clearly demonstrated the association of the oleaginous yeast character to the strain level, contrarily to the species-level linkage, as usually stated.This work was supported by the European project “VOLATILE - Biowaste derived volatile fatty acid platform for biopolymers, bioactive compounds and chemical building blocks “(Call H2020-NMBP-BIO-2016 Grant agreement No. 720777) and by the strategic programme UID/BIA/04050/2013 (POCI-01- 0145-FEDER-007569) funded by national funds through the FCT I.P., by the ERDF through the COMPETE2020

    Elasmobranch responses to experimental warming, acidification, and oxygen loss—a meta-analysis

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    Despite the long evolutionary history of this group, the challenges brought by the Anthropocene have been inflicting an extensive pressure over sharks and their relatives. Overexploitation has been driving a worldwide decline in elasmobranch populations, and rapid environmental change, triggered by anthropogenic activities, may further test this group's resilience. In this context, we searched the literature for peer-reviewed studies featuring a sustained (>24 h) and controlled exposure of elasmobranch species to warming, acidification, and/or deoxygenation: three of the most pressing symptoms of change in the ocean. In a standardized comparative framework, we conducted an array of mixed-model meta-analyses (based on 368 control-treatment contrasts from 53 studies) to evaluate the effects of these factors and their combination as experimental treatments. We further compared these effects across different attributes (lineages, climates, lifestyles, reproductive modes, and life stages) and assessed the direction of impact over a comprehensive set of biological responses (survival, development, growth, aerobic metabolism, anaerobic metabolism, oxygen transport, feeding, behavior, acid-base status, thermal tolerance, hypoxia tolerance, and cell stress). Based on the present findings, warming appears as the most influential factor, with clear directional effects, namely decreasing development time and increasing aerobic metabolism, feeding, and thermal tolerance. While warming influence was pervasive across attributes, acidification effects appear to be more context-specific, with no perceivable directional trends across biological responses apart from the necessary to achieve acid-base balance. Meanwhile, despite its potential for steep impacts, deoxygenation has been the most neglected factor, with data paucity ultimately precluding sound conclusions. Likewise, the implementation of multi-factor treatments has been mostly restricted to the combination of warming and acidification, with effects approximately matching those of warming. Despite considerable progress over recent years, research regarding the impact of these drivers on elasmobranchs lags behind other taxa, with more research required to disentangle many of the observed effects. Given the current levels of extinction risk and the quick pace of global change, it is further crucial that we integrate the knowledge accumulated through different scientific approaches into a holistic perspective to better understand how this group may fare in a changing ocean

    Influence of thickness and coatings morphology in the antimicrobial performance of zinc oxide coatings

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    "Author's copy"In this research work, the production of undoped and silver (Ag) doped zinc oxide (ZnO) thin films for food-packaging applications were developed. The main goal was to determine the influence of coatings morphology and thickness on the antimicrobial performance of the produced samples. The ZnO based thin films were deposited on PET (Polyethylene terephthalate) substrates by means of DC reactive magnetron sputtering. The thin films were characterized by optical spectroscopy, X-Ray Diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Scanning Electron Microscopy (SEM). The antimicrobial performance of the undoped and Ag-doped ZnO thin films was also evaluated. The results attained have shown that all the deposited zinc oxide and Ag-doped ZnO coatings present columnar morphology with V-shaped columns. The increase of ZnO coatings thickness until 200 nm increases the active surface area of the columns. The thinner samples (50 and 100 nm) present a less pronounced antibacterial activity than the thickest ones (200–600 nm). Regarding Ag-doped ZnO thin films, it was verified that increasing the silver content decreases the growth rate of Escherichia coli and decreases the amount of bacteria cells present at the end of the experiment.The work described in this paper was supported by project NANOPACKSAFER: NANO-engineered PACKaging systems for improving quality, SAFEty and health characteristics of foods, Portugal-Spain International Nanotechnology Laboratory Nanotechnology Projects Call; and also by the FEDER funding through the COMPETE program and FCT PEst-C/BIA/UI4050/2011 project

    Accreditation under the International Standard ISO 15189: Experience of a Genetics Laboratory in DNA Sequencing

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    Introduction: Health care is to some extent influenced by the results of laboratory tests. In order to provide the best care for the patient, laboratories must seek to achieve high levels of quality and competence. International Standard ISO 15189 specifies these requirements and may be used by laboratories to perform accredited genetic tests of materials derived from the human body. Here we describe the procedures to establish Accreditation of DNA sequencing in our laboratory and the first Accreditation of its kind in Portugal. Methods: Our laboratory started to prepare to comply with ISO 15189 Accreditation requirements for DNA sequencing in 2010. Documents describing administrative and technical procedures of the sequencing workflow including sample registries, laboratory protocols, operation and maintenance of equipments, as well as preparation and use of reagents were produced. Regular examination of laboratory equipments by an external entity was implemented to confirm compliance with working requirements. Requisites for personnel training and demonstration of competence were also implemented. The laboratory participated regularly in the DNA sequencing scheme organized by the European Molecular Genetics Quality Network (EMQN). Results: The laboratory obtained formal recognition by Instituto Português de Acreditação (IPAC) in May 2014. A maximum genotyping score for DNA sequencing has been obtained in the external quality assessment scheme since 2010. Sequencing quality measured in terms of the quality read overlap metrics is currently of approximately 96% according to the EMQN scheme. The laboratory processes and analyzes an average of 28.750 samples per year. Discussion: Accreditation of a genetic test under ISO 15189 is a highly demanding and laborious task for a genetic laboratory. However, it is an important step in order to guarantee the highest quality and reproducibility of genetic test results

    A composite indicator for supply chain performance measurement: a case study in a manufacturing company

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    This paper proposes a methodology to develop and implement a Composite Indicator (CI) to measure the performance of Supply Chain processes. It reflects the aggregation of individual measures, related to the same process, with a weighted average, in order to assess the global performance in terms of both efficiency and effectiveness. Through a case study in a manufacturing company, a concept validation was performed by implementing the methodology in the Return process of the Supply Chain. The results showed that the combination between a Composite Indicator and a Business Intelligence tool provides a better understanding of the overall performance of a given process, facilitating also the identification of root causes. This paper aims to contribute to the supply chain performance management research field, proposing a methodology to implement a Composite Indicator, which is a topic insufficiently explored in the existent literature.- This work has been supported by national funds through FCT - Fundacao para a Ciencia e Tecnologia within the Project Scope: UID/CEC/00319/2019

    Towards an approach to assess Supply Chain Quality Management maturity

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    Maturity models have been developed in order to help companies to improve organizational performance. Furthermore, due to the globalization and the growing competition, companies need to increase the competitiveness through operational efficiency, internally and in the entire supply chain.In this paper, an approach for the design and implementation of a Supply Chain Quality Management maturity model is presented.The concept of Supply Chain Quality Management has been developed in order to achieve a good integration between the two approaches: Quality Management and Supply Chain Management, and how such integration can help and support the companies to become more effective and efficient.The proposed approach to assess Supply Chain Quality Management maturity incorporates both quantitative and qualitative information to define several levels corresponding to different integration maturity levels. A case study in a world class company of the automotive industry is being used to validate the approach.- This work is sponsored by the Portugal Incentive System for Research and Technological Development. Project in copromotion no 002814/2015 (iFACTORY 2015-2018)

    Characterization of oral enterobacteriaceae prevalence and resistance profile in chronic kidney disease patients undergoing peritoneal dialysis

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    Chronic Kidney Disease (CKD) is a growing public-health concern worldwide. Patients exhibit compromised immunity and are more prone to infection than other populations. Therefore, oral colonization by clinically relevant members of the Enterobacteriaceae family, major agents of both nosocomial and dialysis-associated infections with frequent prevalence of antibiotic resistances, may constitute a serious risk. Thus, this study aimed to assess the occurrence of clinically relevant enterobacteria and their antibiotic resistance profiles in the oral cavity of CKD patients undergoing peritoneal dialysis (CKD-PD) and compare it to healthy controls. Saliva samples from all the participants were cultured on MacConkey Agar and evaluated regarding the levels of urea, ammonia, and pH. Bacterial isolates were identified and characterized for antibiotic resistance phenotype and genotype. The results showed that CKD-PD patients exhibited significantly higher salivary pH, urea, and ammonia levels than controls, that was accompanied by higher prevalence and diversity of oral enterobacteria. Out of all the species isolated, only the prevalence of Raoultella ornithinolytica varied significantly between groups, colonizing the oral cavity of approximately 30% of CKD-PD patients while absent from controls. Antibiotic resistance phenotyping revealed mostly putative intrinsic resistance phenotypes (to amoxicillin, ticarcillin, and cephalothin), and resistance to sulfamethoxazole (~43% of isolates) and streptomycin (~17%). However, all isolates were resistant to at least one of the antibiotics tested and multidrug resistance isolates were only found in CKD-PD group (31,6%). Mobile genetic elements and resistance genes were detected in isolates of the species Raoultella ornithinolytica, Klebsiella pneumoniae, Klebsiella oxytoca, Escherichia coli, and Enterobacter asburiae, mostly originated from CKD-PD patients. PD-related infection history revealed that Enterobacteriaceae were responsible for ~8% of peritonitis and ~ 16% of exit-site infections episodes in CKD-PD patients, although no association was found to oral enterobacteria colonization at the time of sampling. The results suggest that the CKD-induced alterations of the oral milieu might promote a dysbiosis of the commensal oral microbiome, namely the proliferation of clinically relevant Enterobacteriaceae potentially harboring acquired antibiotic resistance genes. This study highlights the importance of the oral cavity as a reservoir for pathobionts and antibiotic resistances in CKD patients undergoing peritoneal dialysis.info:eu-repo/semantics/publishedVersio

    Participation of Candida albicans transcription factor Rlm1 in cell wall biogenesis and virulence

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    Candida albicans cell wall is important for growth and interaction with the environment. RLM1 is one of the putative transcription factors involved in the cell wall integrity pathway, which plays an important role in the maintenance of the cell wall integrity. In this work we investigated the involvement of RLM1 in the cell wall biogenesis and in virulence. Newly constructed C. albicans Δ/Δrlm1 mutants showed typical cell wall weakening phenotypes, such as hypersensitivity to Congo Red, Calcofluor White, and caspofungin (phenotype reverted in the presence of sorbitol), confirming the involvement of RLM1 in the cell wall integrity. Additionally, the cell wall of C. albicans Δ/Δrlm1 showed a significant increase in chitin (213%) and reduction in mannans (60%), in comparison with the wild-type, results that are consistent with cell wall remodelling. Microarray analysis in the absence of any stress showed that deletion of RLM1 in C. albicans significantly down-regulated genes involved in carbohydrate catabolism such as DAK2, GLK4, NHT1 and TPS1, up-regulated genes involved in the utilization of alternative carbon sources, like AGP2, SOU1, SAP6, CIT1 or GAL4, and genes involved in cell adhesion like ECE1, ALS1, ALS3, HWP1 or RBT1. In agreement with the microarray results adhesion assays showed an increased amount of adhering cells and total biomass in the mutant strain, in comparison with the wild-type. C. albicans mutant Δ/Δrlm1 strain was also found to be less virulent than the wild-type and complemented strains in the murine model of disseminated candidiasis. Overall, we showed that in the absence of RLM1 the modifications in the cell wall composition alter yeast interaction with the environment, with consequences in adhesion ability and virulence. The gene expression findings suggest that this gene participates in the cell wall biogenesis, with the mutant rearranging its metabolic pathways to allow the use of alternative carbon sources.This work was supported by CBMA (Centre of Molecular and Environmental Biology) through the FCT (Fundacao para a Ciencia e Tecnologia) project PEst-C/BIA/UI4050/2011. Yolanda Delgado-Silva was supported by an ALbAN scholarship (No E07D400922PE), and Alexandra Correia by SFRH/BD/31354/2006 fellowship. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript
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