scholarly journals Beauveria bassiana Xylanase: Characterization and Wastepaper Deinking Potential of a Novel Glycosyl Hydrolase from an Endophytic Fungal Entomopathogen

2021 ◽  
Vol 7 (8) ◽  
pp. 668
Author(s):  
Ayodeji Amobonye ◽  
Prashant Bhagwat ◽  
Suren Singh ◽  
Santhosh Pillai
Keyword(s):  
Electron Microscopy ◽  
Beauveria Bassiana ◽  
Specific Activity ◽  
Glycosyl Hydrolase ◽  
Insect Control ◽  
Biotechnological Application ◽  
Optimal Activity ◽  
Beechwood Xylan ◽  
Fungal Entomopathogen ◽  
Scanning Electron

Beauveria bassiana is an entomopathogenic fungus widely used as a biopesticide for insect control; it has also been shown to exist as an endophyte, promoting plant growth in many instances. This study highlights an alternative potential of the fungus; in the production of an industrially important biocatalyst, xylanase. In this regard, Beauveria bassiana SAN01 xylanase was purified to homogeneity and subsequently characterized. The purified xylanase was found to have a specific activity of 324.2 Umg−1 and an estimated molecular mass of ~37 kDa. In addition, it demonstrated optimal activity at pH 6.0 and 45 °C while obeying Michaelis–Menton kinetics towards beechwood xylan with apparent Km, Vmax and kcat of 1.98 mgmL−1, 6.65 μM min−1 and 0.62 s−1 respectively. The enzyme activity was strongly inhibited by Ag2+ and Fe3+ while it was significantly enhanced by Co2+ and Mg2+. Furthermore, the xylanase was shown to effectively deink wastepaper at an optimal rate of 106.72% through its enzymatic disassociation of the fiber-ink bonds as demonstrated by scanning electron microscopy and infrared spectroscopy. This is the first study to demonstrate the biotechnological application of a homogeneously purified glycosyl hydrolase from B. bassiana.

Magnetic Modified Natural Polymers for Biotechnological Application

2014 ◽  
Vol 775-776 ◽  
pp. 738-742
Author(s):  
Elaine Aparecida Santos Carvalho ◽  
Ruben Jesus Sanchez Rodriguez ◽  
Ellen de Freitas Boa Morte ◽  
Mayara de Freitas e Castro ◽  
Darlan Silveira Marum ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Total Mass ◽  
Smooth Surface ◽  
Spherical Geometry ◽  
Biotechnological Application ◽  
Natural Polymers ◽  
Covalent Bonds ◽  
Magnetic Microparticles ◽  
Chemically Modified ◽  
Scanning Electron

Magnetic microparticles were formulated by encapsulating magnetite nanoparticles with cellulose acrylamidemetyl propionate acetate (CAPA) chemically modified with acrylamide (AM) in order to immobilize, through covalent bonds, enzymes. The microparticles were characterized by means of scanning electron microscopy and thermogravimetry. The magnetic CAPA + AM microparticles display a quite regular spherical geometry with smooth surface and a magnetite load corresponding to 11.2% of the total mass. These particles were considered as convenient supports for enzyme immobilization in biodiesel transesterification process.

scholarly journals Cloning and Characterization of the Glucooligosaccharide Catabolic Pathway β-Glucan Glucohydrolase and Cellobiose Phosphorylase in the Marine HyperthermophileThermotoga neapolitana

2000 ◽  
Vol 182 (18) ◽  
pp. 5172-5179 ◽  
Author(s):  
Dinesh A. Yernool ◽  
James K. McCarthy ◽  
Douglas E. Eveleigh ◽  
Jin-Duck Bok
Keyword(s):  
Substrate Specificity ◽  
Specific Activity ◽  
Glycosyl Hydrolase ◽  
Thermotoga Neapolitana ◽  
Glycosyl Hydrolases ◽  
Upstream Gene ◽  
Optimal Activity ◽  
Cellobiose Phosphorylase ◽  
Biphasic Kinetic

ABSTRACT Characterization in Thermotoga neapolitana of a catabolic gene cluster encoding two glycosyl hydrolases, 1,4-β-d-glucan glucohydrolase (GghA) and cellobiose phosphorylase (CbpA), and the apparent absence of a cellobiohydrolase (Cbh) suggest a nonconventional pathway for glucan utilization inThermotogales. GghA purified from T. neapolitana is a 52.5-kDa family 1 glycosyl hydrolase with optimal activity at pH 6.5 and 95°C. GghA releases glucose from soluble glucooligomers, with a preference for longer oligomers:k cat/Km values are 155.2, 76.0, and 9.9 mM−1 s−1 for cellotetraose, cellotriose, and cellobiose, respectively. GghA has broad substrate specificity, with specific activities of 236 U/mg towards cellobiose and 251 U/mg towards lactose. Withp-nitrophenyl-β-glucoside as the substrate, GghA exhibits biphasic kinetic behavior, involving both substrate- and end product-directed activation. Its capacity for transglycosylation is a factor in this activation. Cloning of gghA revealed a contiguous upstream gene (cbpA) encoding a 93.5-kDa cellobiose phosphorylase. Recombinant CbpA has optimal activity at pH 5.0 and 85°C. It has specific activity of 11.8 U/mg and aKm of 1.42 mM for cellobiose, but shows no activity towards other disaccharides or cellotriose. With its single substrate specificity and low Km for cellobiose (compared to GghA's Km of 28.6 mM), CbpA may be the primary enzyme for attacking cellobiose inThermotoga spp. By phosphorolysis of cellobiose, CbpA releases one activated glucosyl molecule while conserving one ATP molecule per disaccharide. CbpA is the first hyperthermophilic cellobiose phosphorylase to be characterized.

Immobilization of Lipase onto Magnetic Nanoparticles for Enantiomer Selective Acetylation of Racemic 1-Phenylethylamine

2019 ◽  
Vol 960 ◽  
pp. 128-132
Author(s):  
Zhi Min Ou ◽  
Jia Ying Pan
Keyword(s):  
Electron Microscopy ◽  
Specific Activity ◽  
Enantiomeric Excess ◽  
Free System ◽  
Magnetic Chitosan ◽  
Solvent Free System ◽  
Magnetic Chitosan Microspheres ◽  
Loading Amount ◽  
Co Precipitation ◽  
Scanning Electron

In this study, magnetic chitosan microspheres (Fe3O4-CTS) were prepared via chemical co-precipitation and cross-linked with lipase using glutaraldehyde to form Fe3O4-CTS-glutaraldehyde-lipase particles. The textural characteristics of Fe3O4-CTS-glutaraldehyde-lipase particles were assessed by scanning electron microscopy. The optimal immobilization conditions were 2.1 mg/mL lipase, 10 mg/mL Fe3O4-CTS-glutaraldehyde, pH 7.5, 30 °C, 2 h. The loading amount of lipase was 126.0 mg/g carrier, and the specific activity reached to 46.7 U/mg. Fe3O4-CTS-glutaraldehyde-lipase particles was used in resolution of racemic 1-phenylethylamine in a solvent-free system. The conversion and enantiomeric excess of (R)-N-(1-phenylethyl)acetamide reached 33.6% and 97%.

Pathogenesis of Human Hair Defects

1974 ◽  
Vol 32 ◽  
pp. 12-13
Author(s):  
P.S. Porter ◽  
T. Aoyagi ◽  
R. Matta
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Human Hair ◽  
Standard Techniques ◽  
Scanning Electron

Using standard techniques of scanning electron microscopy (SEM), over 1000 human hair defects have been studied. In several of the defects, the pathogenesis of the abnormality has been clarified using these techniques. It is the purpose of this paper to present several distinct morphologic abnormalities of hair and to discuss their pathogenesis as elucidated through techniques of scanning electron microscopy.

The Critical Point Drying Method Applied to Scanning Electron Microscopy of L-929 Cells

1970 ◽  
Vol 28 ◽  
pp. 278-279
Author(s):  
Charles TurnbiLL ◽  
Delbert E. Philpott
Keyword(s):  
Electron Microscopy ◽  
Carbon Dioxide ◽  
Surface Tension ◽  
Critical Point ◽  
Freeze Drying ◽  
Attractive Alternative ◽  
Crystal Formation ◽  
Critical Point Drying ◽  
Time Required ◽  
Scanning Electron

The advent of the scanning electron microscope (SCEM) has renewed interest in preparing specimens by avoiding the forces of surface tension. The present method of freeze drying by Boyde and Barger (1969) and Small and Marszalek (1969) does prevent surface tension but ice crystal formation and time required for pumping out the specimen to dryness has discouraged us. We believe an attractive alternative to freeze drying is the critical point method originated by Anderson (1951; for electron microscopy. He avoided surface tension effects during drying by first exchanging the specimen water with alcohol, amy L acetate and then with carbon dioxide. He then selected a specific temperature (36.5°C) and pressure (72 Atm.) at which carbon dioxide would pass from the liquid to the gaseous phase without the effect of surface tension This combination of temperature and, pressure is known as the "critical point" of the Liquid.

Ultrastructural Analysis of the Salivary Glands of Gromphadorhina Portentosa (Schaum)

1977 ◽  
Vol 35 ◽  
pp. 638-639
Author(s):  
P.J. Dailey
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Salivary Glands ◽  
Secretory Vesicles ◽  
The Past ◽  
Transmission Electron ◽  
Means Of Transmission ◽  
Gromphadorhina Portentosa ◽  
Scanning Electron ◽  
Topographical Relief

The structure of insect salivary glands has been extensively investigated during the past decade; however, none have attempted scanning electron microscopy (SEM) in ultrastructural examinations of these secretory organs. This study correlates fine structure by means of SEM cryofractography with that of thin-sectioned epoxy embedded material observed by means of transmission electron microscopy (TEM).Salivary glands of Gromphadorhina portentosa were excised and immediately submerged in cold (4°C) paraformaldehyde-glutaraldehyde fixative1 for 2 hr, washed and post-fixed in 1 per cent 0s04 in phosphosphate buffer (4°C for 2 hr). After ethanolic dehydration half of the samples were embedded in Epon 812 for TEM and half cryofractured and subsequently critical point dried for SEM. Dried specimens were mounted on aluminum stubs and coated with approximately 150 Å of gold in a cold sputtering apparatus.Figure 1 shows a cryofractured plane through a salivary acinus revealing topographical relief of secretory vesicles.

Two- or three-way observations of the identical cell elements within the same sections by LM, TEM and/or SEM

1978 ◽  
Vol 36 (2) ◽  
pp. 82-83 ◽  
Author(s):  
Nakazo Watari ◽  
Yasuaki Hotta ◽  
Yoshio Mabuchi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fine Structure ◽  
Light Microscopy ◽  
Thin Sections ◽  
Transmission Electron ◽  
Identical Cell ◽  
Electron Microscopes ◽  
Scanning Electron

It is very useful if we can observe the identical cell elements within the same sections by light microscopy (LM), transmission electron microscopy (TEM) and/or scanning electron microscopy (SEM) sequentially, because, the cell fine structure can not be indicated by LM, while the color is; on the other hand, the cell fine structure can be very easily observed by EM, although its color properties may not. However, there is one problem in that LM requires thick sections of over 1 μm, while EM needs very thin sections of under 100 nm. Recently, we have developed a new method to observe the same cell elements within the same plastic sections using both light and transmission (conventional or high-voltage) electron microscopes.In this paper, we have developed two new observation methods for the identical cell elements within the same sections, both plastic-embedded and paraffin-embedded, using light microscopy, transmission electron microscopy and/or scanning electron microscopy (Fig. 1).

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