1,720,955 research outputs found
Microbial β-Glucosidase: sources, production and applications
Get PDFCellulose is the most abundant biopolymer in biosphere and the major constituent of plant biomass.
Cellulose polymer is made up of β-glucose units linked by β-glucosidic bonds. Cellulase is an enzymatic system that
catalyzes the hydrolysis of cellulose polymer to glucose monomers. This enzymatic system consists of three
individual enzymes namely endoglucanase, exoglucanase and β-glucosidase which act synergistically to degrade
cellulose molecules into glucose. Cellulases are produced by bacteria, fungi, plants, and animals and used in many
industrial applications such as textile industries, laundry and detergent industries, paper and pulp industry, animal
feeds, and biofuels production. β-Glucosidase is a diverse group of enzymes with wide distribution in bacteria, fungi,
plants and animals and has the potential to be utilized in various biotechnological processes such as biofuel
production, isoflavone hydrolysis, flavor enhancement and alkyl/aryl β-D-glucoside and oligosaccharides synthesis.
Thus, there is increased demand of β-glucosidase production from microbial sources under profitable industrial
conditions. In this review, β-glucosidase classification, localization, and mechanism of action will be described.
Subsequently, the various sources of β-glucosidase for industrial sector will be discussed. Moreover, Fermentation
methods and various parameters affecting β-glucosidase production will be highlighted on the light of recent
findings of different researchers. Finally, β-glucosidase applications in biofuel production, flavors enhancement,
isoflavones hydrolysis, cassava detoxification and oligosaccharide synthesis will be described
Microbial β-Glucosidases: screening, characterization, cloning and applications
Get PDFCellulose is the most abundant biomaterial in the biosphere and the major component of plant biomass.
Cellulase is an enzymatic system required for conversion of renewable cellulose biomass into free sugar for
subsequent use in different applications. Cellulase system mainly consists of three individual enzymes namely:
endoglucanase, exoglucanase and β-glucosidases. β-Glucosidases are ubiquitous enzymes found in all living
organisms with great biological significance. β-Glucosidases have also tremendous biotechnological applications
such as biofuel production, beverage industry, food industry, cassava detoxification and oligosaccharides synthesis.
Microbial β-glucosidases are preferred for industrial uses because of robust activity and novel properties exhibited
by them. This review aims at describing the various biochemical methods used for screening and evaluating
β-glucosidases activity from microbial sources. Subsequently, it generally highlights techniques used for purification
of β-glucosidases. It then elaborates various biochemical and molecular properties of this valuable enzyme such as
pH and temperature optima, glucose tolerance, substrate specificity, molecular weight, and multiplicity. Furthermore,
it describes molecular cloning and expression of bacterial, fungal and metagenomic β-glucosidases. Finally, it
highlights the potential biotechnological applications of β-glucosidases
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
Dispelling 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Characterization of thermophilic β-Glucosidase of rhizospheric bacterial strain (LSKB15) isolated from Cholistan Desert, Pakistan
Get PDFFifty thermophilic bacterial strains isolated from rhizospheric soil of Cholistan desert, Pakistan, and designated as LSKB01-LSKB50 were screened for β-glucosidase gene (bgl) belonging to glycoside hydrolase family 1 (GH 1) using PCR technique. Subsequently, the same strains were screened for extracellular β-glucosidase production using esculin as substrate. All fifty strains were shown to be amplified for conserved region of bgl gene
and to secrete extracellular β-glucosidase. One strain (LSKB15) secreted relative high amount of this enzyme as indicating by size of ferric-esculetin precipitate. This strain was further cultivated on cellulose containing media and β-glucosidase was purified by ammonium sulfate, dialysis and gel filtration chromatography. The purified enzyme showed an optimal temperature of 60°C and an optimal pH of 7. It also showed excellent temperature
and pH stability retaining > 90% activity after incubation for 2 h at pH 5-8 and 40-60°C. Finally, the purified enzyme was run on Native-PAGE and subsequently incubated in phosphate buffer containing 5 mM of 4-methylumbelliferyl-β-D-glucoside (4-MUG) for 15 min at 50°C and visualized by UV light as white band. We concluded that thermophilic LSKB15 β- glucosidase may work with other cellulase to degrade available cellulose
synthesized by plant and the properties exhibited by it such as high temperature and pH stability pointed out its potential industrial importance
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