Reduction in lignin peroxidase activity revealed by effects of lignin content in urea crosslinked starch under aerobic biodegradation in soil

This study characterized the lignin peroxidase (LiP) activity of soil via an enzyme assay to determine the reaction rates and activation energies for 5 wt%, 10 wt%, 15 wt%, and 20 wt% lignin loads in urea crosslinked starch biocomposites. The results revealed that a mixed mode of LiP inhibition occurred after the soil was mixed with these biocomposites with different loads of lignin. Loading of lignin at 5 wt% and 10 wt% lignin resulted in higher values of catalytic activity of LiP: -39.58 and 49.14 µM h-1 g-1 soil, respectively. In comparison, with higher loading of lignin at 15 wt% and 20 wt%, decreases in the catalytic activity of LiP were found and were 28.72 to 37.25 µM h-1 g-1 soil, respectively. The activation energy of LiP increased approximately 1.11- to 1.22-fold when 15 and 20 wt% of lignin was loaded in biocomposites. Research findings established the possibility of unfavorable binding of the LiP to lignin with an increase in the load of lignin, possibly due to the complex structure of intact lignin and presence of inhibitory biodegradation products of lignin accumulates during lignin biodegradation in biocomposites. It was concluded that higher lignin contents (15 wt% and 20 wt%) were effective in reducing the activity of the soil LiP. Hence, higher lignin content possibly protects against losses of lignin, while acting as a filler in the formulation of biocomposites.

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Enhanced Catalytic Dye Decolorization by Microencapsulation of Laccase from P. Sanguineus CS43 in Natural and Synthetic Polymers

Polymers ◽

10.3390/polym12061353 ◽

2020 ◽

Vol 12 (6) ◽

pp. 1353

Author(s):

Natalia Lopez-Barbosa ◽

Ana Lucía Campaña ◽

Juan C. Cruz ◽

Nancy Ornelas-Soto ◽

Johann F. Osma

Keyword(s):

Catalytic Activity ◽

Confocal Microscopy ◽

Fluorescent Dyes ◽

Fold Increase ◽

Dye Decolorization ◽

Reaction Rates ◽

Lower Amount ◽

Poly Vinyl Alcohol ◽

Initial Reaction ◽

Pycnoporus Sanguineus

Polymeric microcapsules with the fungal laccase from Pycnoporus sanguineus CS43 may represent an attractive avenue for the removal or degradation of dyes from wastewaters. Microcapsules of alginate/chitosan (9.23 ± 0.12 µm) and poly(styrenesulfonate) (PSS) (9.25 ± 0.35 µm) were synthesized and subsequently tested for catalytic activity in the decolorization of the diazo dye Congo Red. Successful encapsulation into the materials was verified via confocal microscopy of labeled enzyme molecules. Laccase activity was measured as a function of time and the initial reaction rates were recovered for each preparation, showing up to sevenfold increase with respect to free laccase. The ability of substrates to diffuse through the pores of the microcapsules was evaluated with the aid of fluorescent dyes and confocal microscopy. pH and thermal stability were also measured for encapsulates, showing catalytic activity for pH values as low as 4 and temperatures of about 80 °C. Scanning electron microscope (SEM) analyses demonstrated the ability of PSS capsules to avoid accumulation of byproducts and, therefore, superior catalytic performance. This was corroborated by the direct observation of substrates diffusing in and out of the materials. Compared with our PSS preparation, alginate/chitosan microcapsules studied by others degrade 2.6 times more dye, albeit with a 135-fold increase in units of enzyme per mg of dye. Similarly, poly(vinyl) alcohol microcapsules from degrade 1.7 times more dye, despite an eightfold increase in units of enzyme per mg of dye. This could be potentially beneficial from the economic viewpoint as a significantly lower amount of enzyme might be needed for the same decolorization level achieved with similar encapsulated systems.

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Influence of lignin peroxidase concentration and localisation in lignin biodegradation by Phanerochaete chrysosporium

Applied Microbiology and Biotechnology ◽

10.1007/bf00166793 ◽

1990 ◽

Vol 34 (2) ◽

pp. 264-269 ◽

Cited By ~ 6

Author(s):

Bernard Kurek ◽

Etiiene Odier

Keyword(s):

Phanerochaete Chrysosporium ◽

Lignin Peroxidase ◽

Lignin Biodegradation

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Layer-Like Zeolite X as Catalyst in a Knoevenagel Condensation: The Effect of Different Preparation Pathways and Cation Exchange

Catalysts ◽

10.3390/catal11040474 ◽

2021 ◽

Vol 11 (4) ◽

pp. 474

Author(s):

Jan-Paul Grass ◽

Katharina Klühspies ◽

Bastian Reiprich ◽

Wilhelm Schwieger ◽

Alexandra Inayat

Keyword(s):

Catalytic Activity ◽

Reaction Rate ◽

Knoevenagel Condensation ◽

Ethyl Cyanoacetate ◽

Reaction Rates ◽

Initial Reaction Rate ◽

Comparative Investigation ◽

Morphological Properties ◽

Initial Reaction ◽

Zeolite X

This study is dedicated to the comparative investigation of the catalytic activity of layer-like Faujasite-type (FAU) zeolite X obtained from three different synthesis routes (additive-free route, Li2CO3 route, and TPOAC route) in a liquid-phase Knoevenagel condensation of benzaldehyde and ethyl cyanoacetate to ethyl trans-α-cyanocinnamate. It is shown that the charge-balancing cations (Na+ and K+) and the morphological properties have a strong influence on the apparent reaction rate and degree of conversion. The highest initial reaction rate could be found for the layer-like zeolite X synthesised by the additive-free route in the potassium form. In most cases, the potassium-exchanged zeolites enabled higher maximum conversions and higher reaction rates compared to the zeolite X catalysts in sodium form. However, very thin crystal plates (below 100 nm thickness), similar to those obtained in the presence of TPOAC, did not withstand the multiple aqueous ion exchange procedure, with the remaining coarse crystals facilitating less enhancement of the catalytic activity.

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Quantitative Evaluation of the Production of Ligninolytic Enzymes- Lignin Peroxidase and Manganese Peroxidase by P. Sajor Caju During Coir Pith Composting

CORD ◽

10.37833/cord.v28i1.107 ◽

2012 ◽

Vol 28 (1) ◽

pp. 10 ◽

Cited By ~ 1

Author(s):

Radhakrishnan S

Keyword(s):

Lignin Peroxidase ◽

Manganese Peroxidase ◽

Tamil Nadu ◽

Lignin Content ◽

Ligninolytic Enzymes ◽

Oxidative Enzymes ◽

Aquatic Life ◽

Coir Pith ◽

Coir Fibre ◽

Pleurotus Sajor Caju

Coir is the natural hard fruit fibre extracted from the exocarp of the coconut. The fibre has over 40 percent lignin and is spun into yarn and rope. Coir is used globally for manufacturing floor coverings as home furnishing. The Coir Industry enjoys the status as the largest cottage industry in Kerala giving employment to over a million people, of which 80 percent constitute women. Coir pith is a biomass residue generated during the extraction of coir fibre from coconut husk. Coir pith produced during coir fibre extraction is of environmental concern as its dumping on shore line and leaching of its constituents alter water quality and aquatic life. Management of coir pith is a major problem with all coir industrialists. Hillocks of coir pith accumulate in the vicinities of coir fibre extraction units in Kerala, Tamil Nadu, Andhra Pradesh, Karnataka, and Orissa. These agricultural wastes have traditionally been disposed by burning which resulted in various environmental problems. Therefore, composting is an alternate way to dispose coir pith and is of critical importance. Ligninolytic enzyme production during coir pith composting by Pleurotus sajor caju has been studied in detail. Pleurotus sajor caju produces oxidative enzymes which degrade lignin in the presence of urea as nitrogen source. Substitution of urea with vegetative sources has resulted in the vigorous growth of the mushroom which leads to decreased lignin content and C: N ratio in the biodegraded coir pith. Combination of Azolla and Soya hulls as biological supplements was observed to be the best substitute for lignin peroxidase and manganese peroxidase production. Activity of manganese peroxidase and lignin peroxidase was maximum on the twentieth day of fermentation of coir pith. The level of enzyme activity during biological composting using vegetative sources was compared with the conventional process using urea. The enzyme profile exhibited variation with change in substrate and duration of decomposition. The colonization of Pleurotus sajor caju by its utilization leads to biochemical changes in coir pith converting it into an ideal plant nutrient.

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Mobbing among healthcare workers: A review of research findings and methods of struggling

Journal of Human Sciences ◽

10.14687/jhs.v17i1.5364 ◽

2020 ◽

Vol 17 (1) ◽

pp. 185-193

Author(s):

Aylin Aydın Sayılan ◽

Aykut Aydın

Keyword(s):

Complex Structure ◽

Health Sector ◽

Organizational Productivity ◽

Efficient Manner ◽

Research Findings ◽

Low Performance ◽

Definition Of ◽

The Individual ◽

High Work

Healthcare institutions are organizations with a complex structure where there is a high work stress and it is of utmost importance that services are provided without errors in this complexity. Nowadays, when the hospital management becomes increasingly complex, hospital managers are in a position that influences the success of the hospitals the most. While this situation necessitates the managers to use their time in a more rational and efficient manner, giving a senseless workload to the managers would surely negatively affect the individual and organizational productivity (Karsavuran, 2014). In other words, exposure of the healthcare professionals to mobbing in the professional life causes depressive symptoms to arise, this situation leading to the individual negatively evaluating the quality of his life. As a result, decrease in the job satisfaction of the individual, low performance and reluctance towards the job occur (Yavuzer and Civilidag, 2014). Therefore, it is proposed to clarify the arrangements that prevent managers from applying psychological abuse to their subordinates when determining the superior-subordinate relationships (Yıldız et al., 2013). In this study the titles will include definition of mobbing in health sector, results of mobbing.

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Overexpression of the rice BAHD acyltransferase AT10 increases xylan-bound p-coumarate and reduces lignin in Sorghum bicolor

Biotechnology for Biofuels ◽

10.1186/s13068-021-02068-9 ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Yang Tian ◽

Chien-Yuan Lin ◽

Joon-Hyun Park ◽

Chuan-Yin Wu ◽

Ramu Kakumanu ◽

...

Keyword(s):

Cell Wall ◽

Sorghum Bicolor ◽

Cell Walls ◽

Lignin Content ◽

Complex Structure ◽

Enzymatic Saccharification ◽

Cellulose Microfibrils ◽

Biomass Composition ◽

Bioenergy Crops ◽

Transgenic Lines

Abstract Background The development of bioenergy crops with reduced recalcitrance to enzymatic degradation represents an important challenge to enable the sustainable production of advanced biofuels and bioproducts. Biomass recalcitrance is partly attributed to the complex structure of plant cell walls inside which cellulose microfibrils are protected by a network of hemicellulosic xylan chains that crosslink with each other or with lignin via ferulate (FA) bridges. Overexpression of the rice acyltransferase OsAT10 is an effective bioengineering strategy to lower the amount of FA involved in the formation of cell wall crosslinks and thereby reduce cell wall recalcitrance. The annual crop sorghum represents an attractive feedstock for bioenergy purposes considering its high biomass yields and low input requirements. Although we previously validated the OsAT10 engineering approach in the perennial bioenergy crop switchgrass, the effect of OsAT10 expression on biomass composition and digestibility in sorghum remains to be explored. Results We obtained eight independent sorghum (Sorghum bicolor (L.) Moench) transgenic lines with a single copy of a construct designed for OsAT10 expression. Consistent with the proposed role of OsAT10 in acylating arabinosyl residues on xylan with p-coumarate (pCA), a higher amount of p-coumaroyl-arabinose was released from the cell walls of these lines upon hydrolysis with trifluoroacetic acid. However, no major changes were observed regarding the total amount of pCA or FA esters released from cell walls upon mild alkaline hydrolysis. Certain diferulate (diFA) isomers identified in alkaline hydrolysates were increased in some transgenic lines. The amount of the main cell wall monosaccharides glucose, xylose, and arabinose was unaffected. The transgenic lines showed reduced lignin content and their biomass released higher yields of sugars after ionic liquid pretreatment followed by enzymatic saccharification. Conclusions Expression of OsAT10 in sorghum leads to an increase of xylan-bound pCA without reducing the overall content of cell wall FA esters. Nevertheless, the amount of total cell wall pCA remains unchanged indicating that most pCA is ester-linked to lignin. Unlike other engineered plants overexpressing OsAT10 or a phylogenetically related acyltransferase with similar putative function, the improvements of biomass saccharification efficiency in sorghum OsAT10 lines are likely the result of lignin reductions rather than reductions of cell wall-bound FA. These results also suggest a relationship between xylan-bound pCA and lignification in cell walls.

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Catalytic activity of modified silicates: I. Dehydration of ethanol catalysed by acidic sepiolite

Clay Minerals ◽

10.1180/claymin.1987.022.4.06 ◽

1987 ◽

Vol 22 (4) ◽

pp. 423-433 ◽

Cited By ~ 20

Author(s):

A. Corma ◽

J. Perez-Pariente

Keyword(s):

Catalytic Activity ◽

Reaction Rates ◽

Product Distribution ◽

Operational Variables ◽

Parallel Reactions ◽

Kinetics Of

AbstractThe kinetics of the dehydration of ethanol on acidic Al3+-exchanged sepiolite has been studied. The product distribution indicates that the formation of diethylether and ethylene takes place by a series of consecutive and parallel reactions. A mechanism for the formation of both products has been derived by studying the influence of different operational variables on the reaction rates.

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Platinum loaded tin dioxide: a model system for unravelling the interplay between heterogeneous catalysis and gas sensing

Journal of Materials Chemistry A ◽

10.1039/c7ta08781k ◽

2018 ◽

Vol 6 (5) ◽

pp. 2034-2046 ◽

Cited By ~ 43

Author(s):

David Degler ◽

Sabrina A. Müller ◽

Dmitry E. Doronkin ◽

Di Wang ◽

Jan-Dierk Grunwaldt ◽

...

Keyword(s):

Catalytic Activity ◽

Heterogeneous Catalysis ◽

Structure Function ◽

Tin Dioxide ◽

Control Mechanism ◽

Gas Sensing ◽

Complex Structure ◽

Model System

The presented work unravels the complex structure–function-relationships of Pt-loaded SnO2, namely the sensitization by a Fermi-control mechanism and relation of catalytic activity and gas sensing effect.

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Effect of structural variability and flexibility of aliphatic diamines on self-assembly of host-guest coordination polymers constructed of copper cyanide networks: Structure study and catalytic activity

10.21203/rs.3.rs-288076/v1 ◽

2021 ◽

Author(s):

Safaa Eldin H. Etaiw ◽

Safaa N. Abdou Nabih Abdou

Keyword(s):

Catalytic Activity ◽

Self Assembly ◽

Complex Structure ◽

Building Blocks ◽

Structure Study ◽

Ambient Conditions ◽

Structural Variability ◽

3D Network ◽

Aliphatic Diamines ◽

Networks Structure

Abstract A new 3D-host-guest supramolecular coordination polymer (SCP); ∞3[(Cu3(CN)3)2.(DAHP)], 1 [1,7-diaminoheptane=.(DAHP)] had been synthesized by self-assembly at ambient conditions. X-ray single crystal diffraction of SCP 1 indicated the formation of two-fold [Cu3(CN)3]2 units containing tetrahedral copper(I) atoms which are arranged in unique way to create 3D-network. The neutral [Cu3(CN)3]2 building blocks create unique complex structure containing the minicycle [Cu2(μ3-CN)2] motif with wide cavities enable to capsulate the long chain DAHP as guest molecule. The topology of 1 had been studied by elemental analysis, IR-spectra and thermogravimetric analyses. The topology of 1 had been compared with the prototype SCP containing different aliphatic diamines which indicated the effect of structural variability and flexibility of aliphatic diamines on the network structure of these SCP. The catalytic and photo-catalytic activity of 1 was studied for mineralization of methylene blue (MB) utilizing H2O2 as an oxidant.

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