scholarly journals Truncated Expression of a Carboxypeptidase A from Bovine Improves Its Enzymatic Properties and Detoxification Efficiency of Ochratoxin A

Toxins ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 680
Author(s):  
Lu Xiong ◽  
Mengxue Peng ◽  
Meng Zhao ◽  
Zhihong Liang
Keyword(s):  
Ochratoxin A ◽  
Industrial Applications ◽  
Optimum Temperature ◽  
Carboxypeptidase A ◽  
Maximum Reaction Rate ◽  
Maximum Reaction ◽  
Toxic Product ◽  
Wide Range ◽  
Ochratoxin Α ◽  
Penicillium Spp

Ochratoxin A (OTA) is a toxic secondary metabolite produced mainly by Penicillium spp. and Aspergillus spp. and commonly found in foodstuffs and feedstuffs. Carboxypeptidase A (CPA) can hydrolyze OTA into the non-toxic product ochratoxin α, with great potential to realize industrialized production and detoxify OTA in contaminated foods and feeds. This study constructed a P. pastoris expression vector of mature CPA (M-CPA) without propeptide and signal peptide. The results showed that the degradation rate of OTA by M-CPA was up to 93.36%. Its optimum pH was 8, the optimum temperature was 40 °C, the value of Km was 0.126 mmol/L, and the maximum reaction rate was 0.0219 mol/min. Compared with commercial CPA (S-CPA), the recombinant M-CPA had an improve stability, for which its optimum temperature increased by 10 °C and stability at a wide range pH, especially at pH 3–4 and pH 11. M-CPA could effectively degrade OTA in red wine. M-CPA has the potential for industrial applications, such as can be used as a detoxification additive for foods and feeds.

A Spectrophotometric Procedure, Using Carboxypeptidase A, for the Quantitative Measurement of Ochratoxin A

1976 ◽  
Vol 59 (1) ◽  
pp. 128-129
Author(s):  
Karl Hult ◽  
Sten Gatenbeck
Keyword(s):  
Quantitative Determination ◽  
Ochratoxin A ◽  
Quantitative Measurement ◽  
Carboxypeptidase A ◽  
Excitation Spectra ◽  
Fluorescence Excitation ◽  
Fluorescence Excitation Spectra ◽  
Ochratoxin Α ◽  
The Difference

Abstract In the method described, ochratoxin A is cleaved into ochratoxin α (free isocoumarin chromophore) and phenylalanine, using carboxypeptidase. Detection is based on the difference in fluorescence excitation spectra of ochratoxin A (380 nm, maximum) and ochratoxin α (340 nm, maximum). The quantitation of ochratoxin A is based on the loss of fluorescence intensity at 380 nm. The method has been used for the quantitative determination of as little as 4 μg ochratoxin A/kg barley and barley meal but it could be extended to other products.

New Recombinant Phytase from Kosakonia sacchari: characteristic and biotechnological potential

2019 ◽  
Vol 35 (4) ◽  
pp. 33-41
Author(s):  
L.N. Borshchevskaya ◽  
A.N. Kalinina ◽  
N.V. Bulushova ◽  
S.P. Syneoky ◽  
S.P. Voronin ◽  
...  
Keyword(s):  
Pichia Pastoris ◽  
Specific Activity ◽  
Ministry Of Education ◽  
Maximum Reaction Rate ◽  
Biotechnological Potential ◽  
Resource Center ◽  
Codon Composition ◽  
Maximum Reaction ◽  
Wide Range ◽  
Recombinant Phytase

A DNA sequence from Kosakonia sacchari that according to automated computer analysis is believed to correspond to a gene for histidine acid phytase has been selected from the GenBank database. The sequence was optimized for codon composition, synthesized, cloned and expressed in Pichia pastoris. Main characteristics of the purified recombinant enzyme were determined. It was established that the values of pH=4.5 and temperature of 50 °C are optimal for the phytase functioning. The values of specific activity, Michaelis constant (Km) and maximum reaction rate (Vmax) with phytate as a substrate were 1470 U/mg, 193 uM and 2167 umol/(min ∙ mg), respectively. It was shown that the enzyme was characterized by a wide range of working pH. Therefore, the properties of a new recombinant phytase allow us to consider it as a high-potential enzyme for agrobiotechnology. histidine acid phosphatases, Kosakonia sacchari phytase, Pichia pastoris The work was financially supported by the Ministry of Education and Science of Russian Federation (Unique Project Identifier RFMEFI57917X0145) and was carried out using the Multipurpose Scientific Installation of National Bio-resource Center «All-Russian Collection of Industrial Microorganisms», NRC «Kurchatov Institute» - GOSNIIGENETIKA.

A superefficient ochratoxin A hydrolase with promising potential for industrial applications

2021 ◽  
Author(s):  
Han Luo ◽  
Gan wang ◽  
Nan Chen ◽  
Zemin Fang ◽  
Yazhong Xiao ◽  
...  
Keyword(s):  
Ochratoxin A ◽  
Degradation Mechanism ◽  
Kinetic Constant ◽  
Industrial Applications ◽  
Detoxification Enzymes ◽  
Toxicological Effects ◽  
Catalytic Sites ◽  
Ochratoxin Α ◽  
Detoxifying Enzyme ◽  
Temperature Adaptability

As the most seriously controlled mycotoxin produced by Aspergillus spp. and Penicillium spp., ochratoxin A (OTA) results in various toxicological effects and widely contaminates agro-products. Biological detoxification of OTA is the most priority in food and feed industry, but currently available detoxification enzymes are relatively low effectiveness in time and cost. Here we show a superefficient enzyme ADH3 identified from Stenotrophomonas acidaminiphila with a strong ability to transform OTA into non-toxic ochratoxin-α by acting as an amidohydrolase. Recombinant ADH3 (1.2 μg/mL) completely degrades 50 μg/L OTA within 90 seconds, while the availably most efficient OTA hydrolases takes several hours. The kinetic constant showed that rADH3 ( Kcat/Km ) catalytic efficiency was 56.7-35000 times higher than those of previous hydrolases rAfOTase, rOTase and commercial carboxypeptidase A (CPA). Protein structure-based assay suggested that ADH3 has a preference for hydrophobic residues to form a larger hydrophobic area than other detoxifying enzymes at the cavity of the catalytic sites, and this structure makes the OTA easier to access to catalytic sites. In addition, ADH3 shows considerable temperature adaptability to exert hydrolytic function at the temperature down to 0°C or up to 70°C. Collectively, we report a superefficient OTA detoxifying enzyme with promising potential for industrial applications. IMPORTANCE Ochratoxin A (OTA) can result in various toxicological effects and widely contaminates agro-products and feedstuffs. OTA detoxifications by microbial strains and bio-enzymes are significant to food safety. Although previous studies showed OTA could be transformed through several pathways, the ochratoxin-α pathway is recognized as the most effective one. However, the most currently available enzymes are not efficient enough. Here, a superefficient hydrolase ADH3 which can completely transform 50 μg/L OTA into ochratoxin-α within 90 seconds was screened and characterized. The hydrolase ADH3 shows considerable temperature adaptability (0-70°C) to exert the hydrolytic function. Findings of this study supplied an efficient OTA detoxifying enzyme and predicted the superefficient degradation mechanism which lay a foundation for future industrial applications.

Degradation of ochratoxin A by supernatant and ochratoxinase of Aspergillus niger W-35 isolated from cereals

2020 ◽  
Vol 13 (2) ◽  
pp. 287-298
Author(s):  
M. Zhao ◽  
X.Y. Wang ◽  
S.H. Xu ◽  
G.Q. Yuan ◽  
X.J. Shi ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Food Safety ◽  
Aspergillus Niger ◽  
Ochratoxin A ◽  
Promising Strategy ◽  
Ochratoxin Α ◽  
Food And Feed ◽  
Commercial Feeds ◽  
Penicillium Spp

Ochratoxin A (OTA) is a mycotoxin produced by Aspergillus spp. and Penicillium spp. and poses a threat to food safety. Biodegradation may be a promising strategy for reducing the OTA contamination in the future. In this study, Aspergillus niger strain W-35 was isolated from cereals and studied for its ability to degrade OTA. Results showed that the supernatant of W-35 could degrade OTA both in vitro and in commercial feeds after incubation at 37 °C for 12 h by 78.0 and 37.0%, respectively. Ochratoxin α (OTα) was assayed as a degradation product by HPLC-FLD. Furthermore, an enzyme specific for OTA degradation (ochratoxinase, OTase) obtained from W-35 was successfully expressed in Escherichia coli BL21, and degraded OTA at a rate of 85.1% for 12 h. These results indicated that this OTA degradation is enzymatic and that the responsible enzyme is extracellular OTase. Reliable degradation of OTA has the potential for wide-ranging applications in the food and feed industries.

scholarly journals Screening, production and partial characterization of proteases from microbial isolates obtained from waste dumpsites

2021 ◽  
Vol 1 (2) ◽  
pp. 45-53
Author(s):  
Amos Ndarubu Tsado ◽  
Evans Chidi Egwim ◽  
Solomon Bankole Oyeleke ◽  
Oluwatosin Kudirat Shittu
Keyword(s):  
Sewage Sludge ◽  
Kinetic Parameters ◽  
Proteolytic Enzymes ◽  
Industrial Applications ◽  
Physical Parameters ◽  
Optimum Temperature ◽  
Domestic Waste ◽  
Penicillium Sp ◽  
Wide Range ◽  
Active Protease

Background: Proteases are proteolytic enzymes having a wide range of applications in various industries such as the food industry, pharmaceutical industry, medicine, leather and textile. Microorganisms are considered potentially to be the most suitable sources of proteases. Prior to industrial applications of proteases, it is important to investigate physical parameters affecting their enzyme activities. Methods: The microorganisms isolated from different waste dumpsites were screened for proteolytic activity using casein as a substrate. The optimum temperature and pH and kinetic parameters such as Km, Vmax, specific activities and Kcat of the proteases produced were determined to ascertain their industrial prospects. Results: The results obtained showed that A. niger, A. flavus, Penicillium sp, Muccor and Fusarium sp. are the active protease producing fungal isolates while B. subtilis and B. megaterium are the active protease producing bacterial isolates obtained from waste dumpsites. The optimum temperature and pH values of the proteases produced from these isolates were recorded within a close range of 50-60 oC and 8-9 respectively. The protease produced from Penicillium sp isolated from sewage sludge was observed to have maximum Vmax (222.2U/ml) while protease produced from B. subtilis isolated from domestic waste dumpsite was recorded to have the minimum Km value (0.244mg/ml). The protease produced from B. megaterium isolated from the abattoir site was observed to have the highest specific activity (659.02U/mg) while the protease produced from B. subtilis isolated from refuse dumpsite was observed to have a maximum Kcat value (26.42 s-1). Conclusion: These results show that proteases produced by the isolates obtained from; abattoir sites, refuse waste dumpsite, sewage sludge, domestic waste dumpsites, possess remarkable kinetic parameters that are crucial for their industrial applications

Substituent Effects on the Thermal Decomposition of Phosphate Esters on Ferrous Surfaces

2019 ◽  
Author(s):  
James Ewen ◽  
Carlos Ayestaran Latorre ◽  
Arash Khajeh ◽  
Joshua Moore ◽  
Joseph Remias ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Film Formation ◽  
Substituent Effects ◽  
Vapour Phase ◽  
Industrial Applications ◽  
Phosphate Esters ◽  
Antiwear Additives ◽  
Formation Mechanisms ◽  
Phosphate Ester ◽  
Wide Range

<p>Phosphate esters have a wide range of industrial applications, for example in tribology where they are used as vapour phase lubricants and antiwear additives. To rationally design phosphate esters with improved tribological performance, an atomic-level understanding of their film formation mechanisms is required. One important aspect is the thermal decomposition of phosphate esters on steel surfaces, since this initiates film formation. In this study, ReaxFF molecular dynamics simulations are used to study the thermal decomposition of phosphate esters with different substituents on several ferrous surfaces. On Fe<sub>3</sub>O<sub>4</sub>(001) and α-Fe(110), chemisorption interactions between the phosphate esters and the surfaces occur even at room temperature, and the number of molecule-surface bonds increases as the temperature is increased from 300 to 1000 K. Conversely, on hydroxylated, amorphous Fe<sub>3</sub>O<sub>4</sub>, most of the molecules are physisorbed, even at high temperature. Thermal decomposition rates were much higher on Fe<sub>3</sub>O<sub>4</sub>(001) and particularly α-Fe(110) compared to hydroxylated, amorphous Fe<sub>3</sub>O<sub>4</sub>. This suggests that water passivates ferrous surfaces and inhibits phosphate ester chemisorption, decomposition, and ultimately film formation. On Fe<sub>3</sub>O<sub>4</sub>(001), thermal decomposition proceeds mainly through C-O cleavage (to form surface alkyl and aryl groups) and C-H cleavage (to form surface hydroxyls). The onset temperature for C-O cleavage on Fe<sub>3</sub>O<sub>4</sub>(001) increases in the order: tertiary alkyl < secondary alkyl < primary linear alkyl ≈ primary branched alkyl < aryl. This order is in agreement with experimental observations for the thermal stability of antiwear additives with similar substituents. The results highlight surface and substituent effects on the thermal decomposition of phosphate esters which should be helpful for the design of new molecules with improved performance.</p>

PLATINUM

Alloy Digest ◽  
1970 ◽  
Vol 19 (11) ◽  
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Heat Treating ◽  
Industrial Applications ◽  
High Melting ◽  
High Melting Point ◽  
White Metal ◽  
Temperature Performance ◽  
Wide Range ◽  
Corrosion And Oxidation

Abstract PLATINUM is a soft, ductile, white metal which can be readily worked either hot or cold. It has a wide range of industrial applications because of its excellent corrosion and oxidation resistance and its high melting point. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Pt-1. Producer or source: Matthey Bishop Inc..

scholarly journals Modelling and Multi-Objective Optimization of the Sulphur Dioxide Oxidation Process

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 1072
Author(s):  
Mohammad Reza Zaker ◽  
Clémence Fauteux-Lefebvre ◽  
Jules Thibault
Keyword(s):  
Sulphuric Acid ◽  
Sulphur Dioxide ◽  
Variable Number ◽  
Inlet Temperature ◽  
Multi Objective Optimization ◽  
Absorption Column ◽  
Maximum Reaction Rate ◽  
Multi Objective ◽  
Maximum Reaction

Sulphuric acid (H2SO4) is one of the most produced chemicals in the world. The critical step of the sulphuric acid production is the oxidation of sulphur dioxide (SO2) to sulphur trioxide (SO3) which takes place in a multi catalytic bed reactor. In this study, a representative kinetic rate equation was rigorously selected to develop a mathematical model to perform the multi-objective optimization (MOO) of the reactor. The objectives of the MOO were the SO2 conversion, SO3 productivity, and catalyst weight, whereas the decisions variables were the inlet temperature and the length of each catalytic bed. MOO studies were performed for various design scenarios involving a variable number of catalytic beds and different reactor configurations. The MOO process was mainly comprised of two steps: (1) the determination of Pareto domain via the determination a large number of non-dominated solutions, and (2) the ranking of the Pareto-optimal solutions based on preferences of a decision maker. Results show that a reactor comprised of four catalytic beds with an intermediate absorption column provides higher SO2 conversion, marginally superior to four catalytic beds without an intermediate SO3 absorption column. Both scenarios are close to the ideal optimum, where the reactor temperature would be adjusted to always be at the maximum reaction rate. Results clearly highlight the compromise existing between conversion, productivity and catalyst weight.

scholarly journals The aspects of microbial biomass use in the utilization of selected waste from the agro-food industry

2020 ◽  
Vol 15 (1) ◽  
pp. 787-796 ◽  
Author(s):  
Marek Kieliszek ◽  
Kamil Piwowarek ◽  
Anna M. Kot ◽  
Katarzyna Pobiega
Keyword(s):  
Food Industry ◽  
Industrial Applications ◽  
Waste Products ◽  
Yeast Biomass ◽  
Wide Range ◽  
Innovative Solutions ◽  
Biomass Management ◽  
Effective Use ◽  
Modern Technologies ◽  
Biomass Of Microorganisms

AbstractCellular biomass of microorganisms can be effectively used in the treatment of waste from various branches of the agro-food industry. Urbanization processes and economic development, which have been intensifying in recent decades, lead to the degradation of the natural environment. In the first half of the 20th century, problems related to waste management were not as serious and challenging as they are today. The present situation forces the use of modern technologies and the creation of innovative solutions for environmental protection. Waste of industrial origin are difficult to recycle and require a high financial outlay, while the organic waste of animal and plant origins, such as potato wastewater, whey, lignin, and cellulose, is dominant. In this article, we describe the possibilities of using microorganisms for the utilization of various waste products. A solution to reduce the costs of waste disposal is the use of yeast biomass. Management of waste products using yeast biomass has made it possible to generate new metabolites, such as β-glucans, vitamins, carotenoids, and enzymes, which have a wide range of industrial applications. Exploration and discovery of new areas of applications of yeast, fungal, and bacteria cells can lead to an increase in their effective use in many fields of biotechnology.

scholarly journals Jojoba Oil: An Updated Comprehensive Review on Chemistry, Pharmaceutical Uses, and Toxicity

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1711
Author(s):  
Heba A. Gad ◽  
Autumn Roberts ◽  
Samirah H. Hamzi ◽  
Haidy A. Gad ◽  
Ilham Touiss ◽  
...  
Keyword(s):  
Industrial Applications ◽  
Literature Survey ◽  
Jojoba Oil ◽  
Pharmacological Activities ◽  
Wide Range ◽  
Liver Functions ◽  
History Of ◽  
History Of Use ◽  
Pharmaceutical Uses ◽  
Obesity And Cancer

Jojoba is a widely used medicinal plant that is cultivated worldwide. Its seeds and oil have a long history of use in folklore to treat various ailments, such as skin and scalp disorders, superficial wounds, sore throat, obesity, and cancer; for improvement of liver functions, enhancement of immunity, and promotion of hair growth. Extensive studies on Jojoba oil showed a wide range of pharmacological applications, including antioxidant, anti-acne and antipsoriasis, anti-inflammatory, antifungal, antipyretic, analgesic, antimicrobial, and anti-hyperglycemia activities. In addition, Jojoba oil is widely used in the pharmaceutical industry, especially in cosmetics for topical, transdermal, and parenteral preparations. Jojoba oil also holds value in the industry as an anti-rodent, insecticides, lubricant, surfactant, and a source for the production of bioenergy. Jojoba oil is considered among the top-ranked oils due to its wax, which constitutes about 98% (mainly wax esters, few free fatty acids, alcohols, and hydrocarbons). In addition, sterols and vitamins with few triglyceride esters, flavonoids, phenolic and cyanogenic compounds are also present. The present review represents an updated literature survey about the chemical composition of jojoba oil, its physical properties, pharmacological activities, pharmaceutical and industrial applications, and toxicity.

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