scholarly journals Novel DyP from the basidiomycete Pleurotus sapidus: substrate screening and kinetics

Biocatalysis ◽  
2018 ◽  
Vol 4 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Alexandru Avram ◽  
Arijit Sengupta ◽  
Peter H. Pfromm ◽  
Holger Zorn ◽  
Patrick Lorenz ◽  
...  

AbstractA novel Dye-decolorizing peroxidase from the basidiomycete Pleurotus sapidus was screened for dyedecolorizing peroxidase activity with 2,2‘-azino-bis(3- ethylbenzothiazoline-6-sulfonic acid), Remazol Brilliant Blue R and Guaiacol. Additionally, the catalytic efficiency on degrading β-carotene into volatile products, and the catalyst storage stability with three different additives were also studied. The apparent inhibition constant (KS) was 51.7 μM. Optimal reaction rates (Vmax) and affinity constants (Km) towards the reducing substrates were obtained using Michaelis-Menten kinetic theory. The trend in the calculated Km’s was found to be 7.0 mM > 0.524 mM > 0.051 mM for Guaiacol, 2,2‘-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) and Remazol Brilliant Blue R. The storage stability of the catalyst was evaluated with 7.0% w/v PEG400, 7.0% w/v PEG1450 and 0.1% w/v Tween®80 at 5°C over a period of 45 days. The study revealed the longest activity conservation with PEG1450, where rDyP had lost 30% of initial activity. The enzyme solution presented similar pH and temperature dependence to known fungal dye-decolorizing peroxidases with most prolific enzymatic activities registered at pH 4.0 and temperatures below 30°C. An interesting property of the catalyst was oxidation observed in the absence of hydrogen peroxide.

2020 ◽  
Vol 24 ◽  
Author(s):  
Bubun Banerjee ◽  
Gurpreet Kaur ◽  
Navdeep Kaur

: Metal-free organocatalysts are becoming an important tool for the sustainable developments of various bioactive heterocycles. On the other hand, during last two decades, calix[n]arenes have been gaining considerable attention due to their wide range of applicability in the field of supramolecular chemistry. Recently, sulfonic acid functionalized calix[n] arenes are being employed as an efficient alternative catalyst for the synthesis of various bioactive scaffolds. In this review we have summarized the catalytic efficiency of p-sulfonic acid calix[n]arenes for the synthesis of diverse biologically promising scaffolds under various reaction conditions. There is no such review available in the literature showing the catalytic applicability of p-sulfonic acid calix[n]arenes. Therefore, we strongly believe that this review will surely attract those researchers who are interested about this fascinating organocatalyst.


RSC Advances ◽  
2016 ◽  
Vol 6 (27) ◽  
pp. 22395-22410 ◽  
Author(s):  
K. Z. Elwakeel ◽  
A. A. El-Bindary ◽  
A. Ismail ◽  
A. M. Morshidy

Chitosan, glycidyl methacrylate (synthetic polymer) and magnetite are combined to produce novel magnetic macro-reticular hybrid synthetic–natural materials which are shown to be effective sorbents for RBBR ions.


2000 ◽  
Vol 78 (8) ◽  
pp. 1052-1059 ◽  
Author(s):  
C Aliaga ◽  
E A Lissi

Stable free radicals derived from 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS·+) have been extensively employed to monitor the antioxidant capacity of biological fluids and beverages. Besides reacting with typical antioxidants (such as phenols or thiols) these radicals react with a variety of hydrogen or electron donors. The present work reports on the kinetics and mechanism of these radical reactions with several amino acids. Reaction rates notably increase when the pH of the media increases and, when measured under similar conditions, follows the ordercysteine > > tryptophan > tyrosine > histidine > cystineThe kinetics of the process is interpreted in terms of a mechanism comprising an initial pH dependent reversible step, followed by secondary reactions of the substrate derived radical with itself or with another ABTS·+; this simple three-step mechanism leads to very complex kinetic expressions. The specific rate constants of several of the elementary steps were determined by working under a wide range of substrate, radical, and ABTS concentrations. The values obtained for the initial interaction between the ABTS derived radical and the substrate range from 0.5 M–1 s–1 to 1.9 × 106 M–1 s–1 for histidine and cysteine, respectively.Key words: ABTS radical cation, 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid), amino acids, kinetics.


2021 ◽  
Author(s):  
Ali H. Jawad ◽  
Ahmed Saud Abdulhameed ◽  
Elmira Kashi ◽  
Zaher Mundher Yaseen ◽  
Zeid A. ALOthman ◽  
...  

Abstract Kaolin clay (KN) was employed as an inorganic filler to modify a cross-linked chitosan-glyoxal as Schiff’s-based chitosan composite derivative (CTS-GLY). The resulting (CTS-GLY/KN) was found to be a promising composite synthetic biopolymer that can be potentially utilized for color removal as well as COD reduction of an industrial anionic dye (remazol brilliant blue R, RBBR). The surface porosity, crystallinity, morphology, functionality, charge, and amine content of the CTS-GLY/KN were studied using BET, XRD, SEM, FTIR, pHpzc and pH-potentiometric titration analyses, respectively. Response surface methodology-Box-Behnken design (RSM-BBD) was used to optimize the impact of the main input factors on the color removal and COD reduction of RBBR. The adsorptive performance CTS-GLY/KN towards RBBR was well-defined by both Langmuir and Freundlich isotherm models with highest adsorption capacity of 447.1 mg/g at 30 ˚C. This finding reveals that CTS-GLY/KN can be utilized as a promising, feasible, and environmentally friendly composite-biosorbent for color removal and COD reduction of textile dyes from aqueous medium.


2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Aisha Malik ◽  
S. Hameed ◽  
M. J. Siddiqui ◽  
M. M. Haque ◽  
M. Muneer

Nanocrystalline TiO2particles doped with different concentrations of Cerium (Ce, 1–10%) have been synthesized using sol-gel method. The prepared particles were characterized by standard analytical techniques such as X-ray diffraction (XRD), FTIR and Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM). The XRD analysis shows no change in crystal structure of TiO2after doping with different concentrations of Ce, which indicates the single-phase polycrystalline material. The SEM analysis shows the partial crystalline nature of undoped, and doped TiO2and TEM analysis shows the particle sizes were in the range of 9–14 nm in size. The a.c. analysis shows that the dielectric constantεand dielectric loss tanδdecrease with the increase in frequency. The dielectric property decreases with the increase in dopant concentration. It is also observed that the impedance increases with an increase in dopant concentration. The photocatalytic activity of the synthesized particles (Ce-doped TiO2) with dopant concentration of 9% (Ce) showed the highest photocatalytic activity for the degradation of the dye derivative Remazol Brilliant Blue R in an immersion well photochemical reactor with 500 W halogen linear lamp in the presence of atmospheric oxygen.


Sign in / Sign up

Export Citation Format

Share Document