1,720,974 research outputs found
Directed evolution of an ultrastable carbonic anhydrase from Desulfovibrio vulgaris towards enhanced tolerance to flue gas impurities
No full textCarbonic anhydrases (CAs) have been proved as a highly efficient and selective promoter for conventional Carbon Capture Utilization and Storage (CCUS) industrial processes. The aim of this work was to demonstrate a high-throughput screening system for detecting engineered CAs with resistance to common inhibitors (SO42-, SO32-, NO3-, NO2-) present as major impurities in post-combustion flue gases, maintaining their initial thermostability. We established a screening protocol on solid and liquid assays for selecting mutants generated with error-prone PCR (epCA8.0) maintaining the thermostability of the parent DvCA8.0 but having improved resistance to flue gas inhibitors. A library of around 1000 mutants was created. The mutant E12 (G7D) showed 50 % increased stability for a mix of inhibitors corresponding to total concentration of 300–600 mM and 65 % increased stability to 150 mM, compared to the parent DvCA8.0. To our knowledge, this is the first time that a CA was evolved by protein engineering methods to increase its stability to common flue gas inhibitors. Additionally, we have established a premise for screening and characterization of CA libraries, which has not been clearly addressed previously, as presence of ionic inhibitors significantly change the pH of enzyme assays, while the nature of such screening assays is pH dependent. We envision that this study will open the pathway for the development of highly resistant CAs in the near future, overcoming stability and cost issues that are associated with their limited application in CCUS technologies.Validerad;2025;Nivå 2;2025-06-30 (u5);Full text license: CC BY-NC-ND 4.0;</p
Enzymatic synthesis of bioactive compounds with high potential for cosmeceutical application.
No full textCosmeceuticals are cosmetic products containing biologically active ingredients purporting to offer a pharmaceutical therapeutic benefit. The active ingredients can be extracted and purified from natural sources (botanicals, herbal extracts, or animals) but can also be obtained biotechnologically by fermentation and cell cultures or by enzymatic synthesis and modification of natural compounds. A cosmeceutical ingredient should possess an attractive property such as anti-oxidant, anti-inflammatory, skin whitening, anti-aging, anti-wrinkling, or photoprotective activity, among others. During the past years, there has been an increased interest on the enzymatic synthesis of bioactive esters and glycosides based on (trans)esterification, (trans)glycosylation, or oxidation reactions. Natural bioactive compounds with exceptional theurapeutic properties and low toxicity may offer a new insight into the design and development of potent and beneficial cosmetics. This review gives an overview of the enzymatic modifications which are performed currently for the synthesis of products with attractive properties for the cosmeceutical industry</p
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
A biorefinery approach for the conversion of Cynara cardunculus biomass to active films
Get PDFCardoon (Cynara cardunculus), an herbaceous perennial plant able to grow with high productivity in dry and hot
regions, as well as in unproductive soils, was used as a biomass source for the production of both bioactive
compounds derived from leaves and proteins extracted from seeds. Naviglio® technology was found as an
efficient method to obtain a cardoon leaf extract (CLE) characterized by high phenol content and oxygen
scavenging activity. On the other hand, cardoon proteins (CPs) were demonstrated to give rise to handleable
greenish films endowed with promising mechanical and barrier properties in the presence of glycerol used as
plasticizer. Hence, the CLE was used to functionalize the films that were further characterized. Film microstructure
observed by SEM revealed a good compatibility among CPs and CLE, showing a uniform distribution of
the leaf extract components throughout the film network that reflected, in turn, an improvement in the mechanical
and barrier properties of the obtained material. In addition, the CLE containing films exhibited higher
hydrophobicity, as indicated by the contact angle measurement and by the evaluation of water solubility and
swelling degree experiments. Finally, CLE-containing films showed a marked antioxidant activity, highlighting
the potential of Cynara cardunculus to be exploited as a biorefinery where different low-value renewable biomass
materials are turned in several higher value bio-based products
To salt or not to salt: Optimized production and sequential downstream processing of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and bacterioruberin from Haloferax mediterranei
No full textThis study presents an integrated bioprocess for the sustainable production and simultaneous recovery of two high-value bioproducts – poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and bacterioruberin (BR) – from the halophilic archaeon Haloferax mediterranei. A Response Surface Methodology was applied to optimize key fermentation parameters, such as NaCl concentration, carbon-to-nitrogen (C/N) ratio, and nitrogen source. Both minimal synthetic medium and seawater were assessed, the latter demonstrating potential as a more sustainable alternative to freshwater-based cultivation systems. Optimal PHBV accumulation (25 % gpolymer/gCDW) was achieved under high salinity (167.7 g L−1 NaCl), a C/N ratio of 40, and with KNO3 as the nitrogen source. In contrast, BR production was maximized (7.8 mg L-1) under moderate salinity (100 g L−1) and a lower C/N ratio (8). To enable efficient product separation, a sequential downstream strategy was developed, allowing recovery yields of PHBV and BR comparable to conventional single-product extraction protocols, while reducing reliance on halogenated solvents. Overall, the proposed process supports the valorization of halophilic biomass through a resource-efficient platform, contributing to the development of integrated biorefinery approaches aligned with principles of green and sustainable chemistry
Selection of new fungal strain producing feruloyl esterases for biotechnological applications
No full textDispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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