Degradability of chlorine-free bleachery effluent lignins by two fungi: effects on lignin subunit type and on polymer molecular weight

1994 ◽  
Vol 40 (3) ◽  
pp. 192-197 ◽  
Author(s):  
Matthias Bergbauer ◽  
Claudia Eggert
Keyword(s):  
Manganese Peroxidase ◽  
Trametes Versicolor ◽  
Substantial Reduction ◽  
Pulp Mill ◽  
Oxidation Products ◽  
Free Medium ◽  
Polymer Molecular Weight ◽  
Lignin Phenols ◽  
The Stability ◽  
Cuo Oxidation

A bleachery effluent from a sulfite process pulp mill, which was extracted with alkali and treated with oxygen and hydrogen peroxide (EOP), was treated with two fungi, Trametes versicolor and Stagonospora gigaspora. Trametes versicolor did not cause any depolymerization or degradation of effluent lignins but increased the amount of chromophores, whereas S. gigaspora depolymerized the EOP lignins and caused a substantial reduction in aromatic compounds. For both fungal treatments, CuO oxidation caused a decrease in the yield of the aldehydes within the vanillyl and p-hydroxy phenol families, which was faster than the rates of decrease in the yields of the corresponding acids and ketones. However, only S. gigaspora caused changes in the pattern of the 11 characteristic lignin phenols produced by CuO oxidation, reflecting a preferential metabolism of some phenolic precursors. This fungus decreased the yield of total vanillyl phenols (V), which contributed the bulk of the 11 lignin oxidation products, from 93% initially to 59%. As a consequence, coumaryl (C), syringyl (S), and p-hydroxy phenols (P) became relatively enriched to 1.2, 6.5, and 33%, respectively. The stability of EOP-lignin constituent subunits is S > P > C > V. The two fungi differed significantly in their level of enzyme activities. In effluent-free medium, the ratio of laccase to peroxidase was higher for T. versicolor than for S. gigaspora. The presence of EOP-lignins significantly increased this ratio. No lignin peroxidase was detected but manganese peroxidase and laccase were detected during degradation activities.Key words: lignin phenols, CuO oxidation, laccase, manganese peroxidase, Trametes versicolor, Stagonospora gigaspora

Comparative TG/DTG/DTA+FTIR Studies Concerning the Stability of Some Mineral and Vegetable Electro-Insulating Fluids

2018 ◽  
Vol 69 (9) ◽  
pp. 2366-2371
Author(s):  
Andrei Cucos ◽  
Petru Budrugeac ◽  
Iosif Lingvay ◽  
Adriana Mariana Bors ◽  
Andreea Voina
Keyword(s):  
Vegetable Oils ◽  
Electrical Equipment ◽  
Inert Atmosphere ◽  
Oxidation Products ◽  
Gaseous Products ◽  
Mineral Oils ◽  
Ftir Studies ◽  
Dta Analysis ◽  
Anti Oxidant ◽  
The Stability

Thermal TG/DTG/DTA analysis coupled with FTIR spectroscopy was applied to some sorts of mineral and vegetable oils used in electrical equipment. On heating in inert atmosphere, it was observed that the mineral oils vaporize, while the vegetable oils undergo hydrolysis, yielding fatty acids as main volatiles, as indicated by FTIR. In synthetic air, the FTIR spectra of gaseous products confirm the presence of similar oxidation products, both for mineral and vegetable oils. The TG results indicated that the vegetable-based oils exhibit a substantially higher thermal stability than the mineral oils. The presence or absence of anti-oxidant inhibitors in these oils greatly influences the onset of the oxidation process in air environment factor, as results from the DTA results.

scholarly journals Carrier-microencapsulation using Al-catecholate complex to suppress arsenopyrite oxidation: Evaluation of the coating stability under simulated weathering conditions

2019 ◽  
Vol 268 ◽  
pp. 06002 ◽  
Author(s):  
Kensuke Seno ◽  
Ilhwan Park ◽  
Carlito Tabelin ◽  
Kagehiro Magaribuchi ◽  
Mayumi Ito ◽  
...  
Keyword(s):  
Protective Coating ◽  
Sulfide Mineral ◽  
Sulfide Minerals ◽  
Low Ph ◽  
Oxidation Products ◽  
Arsenic Sulfide ◽  
Catecholate Complex ◽  
Coating Stability ◽  
The Stability

Arsenopyrite (FeAsS) is the most common primary arsenic-sulfide mineral in nature, and its oxidation causes the release of toxic arsenic (As). To mitigate these problems, carrier-microencapsulation (CME), a technique that passivates sulfide minerals by covering their surfaces with a protective coating, has been developed. In the previous study of authors on CME, Al-catecholate complex significantly suppressed arsenopyrite oxidation via electron donating effects of the complex and the formation of an Al-oxyhydroxide coating. For the application of this technique to real tailings, however, further study should be carried out to elucidate long-term effectiveness of the coating to suppress arsenopyrite oxidation. This study investigates the stability of the coating formed on arsenopyrite by Al-based CME using weathering tests. The Al-oxyhydroxide coating suppressed arsenopyrite oxidation until about 50 days of the experiment, but after this, the amounts of oxidation products like dissolved S and As increased due to the gradual dissolution of the coating with time as a result of the low pH of leachate. This suggests that co-disposal of Al-based CME-treated arsenopyrite with minerals that have appropriate neutralization potentials, so that the pH is maintained at around 5 to 8 where Al-oxyhydroxide is stable.

scholarly journals The effect of dihydroquercetin on the stability of consumer properties of chopped semi-finished meat

2021 ◽  
Vol 285 ◽  
pp. 05011
Author(s):  
N. N. Shagaeva ◽  
S. V. Kolobov ◽  
I. A. Zachesova
Keyword(s):  
Meat Products ◽  
Microbiological Quality ◽  
Negative Temperature ◽  
Acid Number ◽  
Oxidation Products ◽  
Raw Material ◽  
Experimental Sample ◽  
Quality Stability ◽  
Increasing Demand ◽  
The Stability

The steadily increasing demand for semi-finished meat products is provided by the constantly expanding product range and improving its quality. In turn, quality stability is an important criterion for increasing sales. The article presents data on the effect of a natural antioxidant-dihydroquercetin on the stability of consumer properties of chopped semi-finished moose meat with the addition of beet fiber when stored at a negative temperature for 216 days. Dihydroquercetin was added in an amount of 0.05% by weight of the raw material. In the course of the work, generally accepted methods of studying organoleptic and microbiological quality indicators were used. The degree of oxidative deterioration of the product was checked by determining the acid, peroxide and thiobarbituric numbers. The conducted studies allowed us to conclude that the use of this food additive allows us to preserve the organoleptic and microbiological properties of the semi-finished product for a longer period by inhibiting the formation of oxidation products. The use of dihydroquercetin contributed to a decrease in the experimental sample of the semi-finished product on day 216 of the peroxide and acid number by 2 times, and the thiobarbituric number by 1.8 times in relation to the control. Thus, by reducing the oxidative damage of the semi-finished product, it is possible to influence its characteristics during storage.

Processing, secretion, and biological properties of a novel growth factor of the fibroblast growth factor family with oncogenic potential

1988 ◽  
Vol 8 (7) ◽  
pp. 2933-2941
Author(s):  
P Delli-Bovi ◽  
A M Curatola ◽  
K M Newman ◽  
Y Sato ◽  
D Moscatelli ◽  
...  
Keyword(s):  
Biological Activity ◽  
Growth Factor ◽  
Kaposi Sarcoma ◽  
Biological Properties ◽  
Fibroblast Growth ◽  
Serum Free Medium ◽  
Free Medium ◽  
Serum Free ◽  
The Stability ◽  
Nih 3T3

We recently reported that the protein encoded in a novel human oncogene isolated from Kaposi sarcoma DNA was a growth factor with significant homology to basic and acidic fibroblast growth factors (FGFs). To study the properties of this growth factor (referred to as K-FGF) and the mechanism by which the K-fgf oncogene transforms cells, we have studied the production and processing of K-FGF in COS-1 cells transfected with a plasmid encoding the K-fgf cDNA. The results show that, unlike basic and acidic FGFs, the K-FGF protein is cleaved after a signal peptide, glycosylated, and efficiently secreted as a mature protein of 176 or 175 amino acids. Inhibition of glycosylation impaired secretion, and the stability of the secreted K-FGF was greatly enhanced by the presence of heparin in the cultured medium. We have used the conditioned medium from transfected COS-1 cells to test K-FGF biological activity. Similar to basic FGF, the K-FGF protein was mitogenic for fibroblasts and endothelial cells and induced the growth of NIH 3T3 mouse cells in serum-free medium. Accordingly, K-fgf-transformed NIH 3T3 cells grew in serum-free medium, consistent with an autocrine mechanism of growth. We have also expressed the protein encoded in the K-fgf protooncogene in COS-1 cells, and it was indistinguishable in its molecular weight, glycosylation, secretion, and biological activity from K-FGF. Taken together, these results suggest that the mechanism of activation of this oncogene is due to overexpression rather than to mutations in the coding sequences.

scholarly journals Influence of Oxygen-Containing Sulfur Flavor Molecules on the Stability of β-Carotene under UVA Irradiation

Molecules ◽  
2019 ◽  
Vol 24 (2) ◽  
pp. 318 ◽  
Author(s):  
Gong-Liang Zhang ◽  
Hong-Yan Wu ◽  
Ying Liang ◽  
Jie Song ◽  
Wei-Qi Gan ◽  
...  
Keyword(s):  
Sulfur Atom ◽  
Critical Role ◽  
Oxidation Products ◽  
First Order ◽  
Uva Irradiation ◽  
First Order Kinetics ◽  
Dynamic Degradation ◽  
The Stability ◽  
Ethanol System ◽  
Β Carotene

The influence of 11 kinds of oxygen-containing sulfur flavor molecules was examined on β-carotene stability under UVA irradiation in ethanol system. Both the effects of sulfides on dynamic degradation of β-carotene and the relation between structure and effect were investigated. The oxidation products of β-carotene accelerated by sulfides under UVA irradiation were also identified. The results indicated that the disulfides had more obvious accelerative effects on the photodegradation of β-carotene than mono sulfides. The degradation of β-carotene after methyl (2-methyl-3-furyl) disulfide (MMFDS), methyl furfuryl disulfide (MFDS) and bis(2-methyl-3-furyl) disulfide (BMFDS) exposure followed first-order kinetics. Furan-containing sulfides such as MMFDS and BMFDS showed more pronounced accelerative effects than their corresponding isomers. The oxidation products were identified as 13-cis-β-carotene, 9,13-di-cis-β-carotene and all-trans-5,6-epoxy-β-carotene. These results suggest that both the sulfur atom numbers and the furan group in oxygen-containing sulfides play a critical role in the photooxidation of β-carotene.

Use of ferrate pre-oxidation in enhancing the treatment of NOM-rich lake waters

2004 ◽  
Vol 4 (4) ◽  
pp. 121-128 ◽  
Author(s):  
L. Wei ◽  
L. Yong-Mei
Keyword(s):  
Substantial Reduction ◽  
Drinking Water Treatment ◽  
Inorganic Particles ◽  
Simple Addition ◽  
The Stability ◽  
Lake Waters ◽  
Iron Manganese ◽  
Total Bacteria ◽  
Low Dosage

Natural organic materials (NOMs) have a very strong influence on the stability of inorganic particles through interactions (e.g. adsorption, coating, and so on), and thus make the surface water with high NOM content difficult to be coagulated. In this study, standard jar tests and a pilot study were conducted to evaluate the effectiveness of ferrate pre-oxidation in enhancing the coagulation of NOM-rich lake water. A substantial reduction of residual turbidity after sedimentation and filtration was obtained by ferrate pre-oxidation at low dosage (1–5 mg L‒1 as K2FeO4). It was suggested that in order to maintain an acceptable residual turbidity, ferrate pre-oxidation can substantially reduce the dosage of coagulant. The improvement of water quality, as indicated by the reduction of color, DOC, iron, manganese, total bacteria, was observed to be similar in nature to the enhancement of residual turbidity. Formation of additional coagulant (Fe (III)) after decomposition was believed to be an important role of ferrate in enhancing coagulation. Ferrate could be employed in drinking water treatment by simple addition of ferrate solution just before coagulation.

scholarly journals Thermal-Oxidation Stability of Soybean Germ Phytosterols in Different Lipid Matrixes

Molecules ◽  
2020 ◽  
Vol 25 (18) ◽  
pp. 4079 ◽  
Author(s):  
Jingnan Chen ◽  
Dami Li ◽  
Guiyun Tang ◽  
Jinfen Zhou ◽  
Wei Liu ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Olive Oil ◽  
Thermal Oxidation ◽  
Loss Rate ◽  
Unsaturated Fatty Acids ◽  
Oxidation Stability ◽  
Oxidation Products ◽  
Higher Temperature ◽  
The Stability ◽  
Thermal Oxidation Stability

The stability of soybean germ phytosterols (SGPs) in different lipid matrixes, including soybean germ oil, olive oil, and lard, was studied at 120, 150, and 180 °C. Results on the loss rate demonstrated that SGPs were most stable in olive oil, followed by soybean germ oil, and lard in a decreasing order. It is most likely that unsaturated fatty acids could oxidize first, compete with consumption of oxygen, and then spare phytosterols from oxidation. The oxidation products of SGPS in non-oil and oil systems were also quantified. The results demonstrated that at relatively lower temperatures (120 and 150 °C), SGPs’ oxidation products were produced the most in the non-oil system, followed by lard, soybean germ oil, and olive oil. This was consistent with the loss rate pattern of SGPs. At a relatively higher temperature of 180 °C, the formation of SGPs’ oxidation products in soybean germ oil was quantitatively the same as that in lard, implying that the temperature became a dominative factor rather than the content of unsaturated fatty acids of lipid matrixes in the oxidation of SGPs.

scholarly journals Comparison of Cholesterol Oxidation Product Preparation Methods for Subsequent Gas Chromatographic Analysis

2004 ◽  
Vol 87 (2) ◽  
pp. 474-480 ◽  
Author(s):  
Maria Teresa Rodriguez-Estrada ◽  
Arianna Costa ◽  
Marco Pelillo ◽  
Maria Fiorenza Caboni ◽  
Giovanni Lercker
Keyword(s):  
Degradation Products ◽  
Oxidation Products ◽  
Gas Chromatography Mass Spectrometry ◽  
Cholesterol Oxidation ◽  
Preparation Methods ◽  
Mass Spectrometry System ◽  
Phase Liquid ◽  
The Stability ◽  
Layer Chromatography ◽  
Cold Saponification

Abstract An evaluation was made of the stability of cholesterol hydroperoxides (CHPs) under the analytical conditions and preparation methods commonly used for determination and quantification of cholesterol oxidation products (COPs). CHPs were prepared by photoxidation and separated by silica thin-layer chromatography. CHPs were individually collected by normal-phase liquid chromatography and then subjected either to reduction or to cold saponification. The corresponding hydroxyl derivatives were generated by reduction, whereas cold saponification gave rise predominantly to 7-ketocholesterol. In another test, silylated and non-silylated CHPs were separately injected into a gas chromatograph at 310°C, collected, and re-injected into a gas chromatography-mass spectrometry system. The silylated CHPs were more stable than the non-silylated ones, giving 7-ketocholesterol, 7α-and 7β-hydroxycholesterol as main degradation products. Two unknown degradation peaks were detected in both silylated and nonsilylated CHPs, having 384 as main m/z fragment. The study of their mass spectra led to the conclusion that peaks A and B correspond to 6α- and 6β-hydroxycholesterol, respectively.

Sign in / Sign up

Export Citation Format

Share Document