On the metabolism of Aspergillus terreus on ammonium nitrate at different pH values

1972 ◽  
Vol 50 (11) ◽  
pp. 2211-2218 ◽  
Author(s):  
Kaiser Naguib ◽  
A. Elbaz Younis ◽  
A. A. Elessawy
Keyword(s):  
Ammonium Nitrate ◽  
Aspergillus Terreus ◽  
Ammonium Nitrogen ◽  
Soluble Nitrogen ◽  
Nitrogen Absorption ◽  
Sugar Absorption ◽  
Ph Values ◽  
Optimum Ph ◽  
Ph Conditions ◽  
Ph Range

One-week-old fungal mats of Aspergillus terreus Thom were fed with buffered Dox's liquid medium containing ammonium nitrate as nitrogen source and adjusted to six different pH values, namely, 3.0, 3.8, 5.4, 6.8, 8.4, and 10.0. Ammonium nitrogen and nitrate nitrogen absorption and utilization, sugar absorption, respiration, and growth were followed over a period of 72 h at 24-h intervals.Ammonium and nitrate were absorbed at all pH values tested, nitrate being preferentially absorbed at the lower, but ammonium at the higher pH values. Low absorption and utilization of nitrogen occurred at the lowest and highest pH values. Optimum pH for sugar absorption was that for nitrogen absorption, though the former was more sensitive to change of pH than the latter. Rate of respiration was affected by sugar and nitrogen absorption. It was optimum at the same optimum for these two processes.There was release of nitrogen from the mycelial cells to the external medium at all pH values tested, but highest release occurred under different pH conditions and was independent of whether ammonium or nitrate absorption was prevailing.In the fungal mats, more soluble nitrogen and less protein were found at the lowest and highest pH values, while less soluble nitrogen and more protein were found at the optimum pH range; a difference apparently more related to pH than to whether ammonium or nitrate was being absorbed.

Effects of incubation fluid pH and fibrolytic enzymes on the in vitro fermentation of pure substrates, assessed using the Reading Pressure Technique (RPT)

2002 ◽  
Vol 2002 ◽  
pp. 208-208 ◽  
Author(s):  
D. Colombatto ◽  
F. L. Mould ◽  
M. K. Bhat ◽  
E. Owen
Keyword(s):  
In Vitro Fermentation ◽  
Commercial Enzyme ◽  
Fibrolytic Enzymes ◽  
Optimum Activity ◽  
Ph Values ◽  
Optimum Ph ◽  
Ph Conditions ◽  
Ph Range ◽  
Optimum Ph Range

Modern feeding practices often lead to ruminal conditions being sub-optimal for fibre digestion. It has been speculated that fibrolytic enzymes, which usually show optimum activity at pH values below 6.0, may be of benefit when applied to diets of high producing animals. This study used a commercial enzyme mixture (EM), already identified as effective; to investigate its optimum pH range with respect to activity and its impact on the fermentation profiles of pure substrates, under differing pH conditions.

Coagulation-Direct Filtration of Soft, Low Alkalinity Humic Waters

1999 ◽  
Vol 40 (9) ◽  
pp. 55-62 ◽  
Author(s):  
Bjørnar Eikebrokk
Keyword(s):  
Natural Organic Matter ◽  
Pilot Scale ◽  
Quality Parameters ◽  
Efficient Removal ◽  
Direct Filtration ◽  
Ph Values ◽  
Optimum Ph ◽  
Calcium Sources ◽  
Ph Conditions ◽  
Removal Efficiencies

Optimisation of coagulation-direct filtration processes with respect to efficient removal of humic substances, i.e. natural organic matter (NOM) has gained a lot of focus in many countries over the last years. This paper presents experimental results from pilot scale research studies aimed at optimising the coagulation-direct filtration process applied to soft and humic raw waters with low turbidity and alkalinity levels. Comprehensive tests of 3 types of raw waters with different NOM content, 5 types of coagulants, and 3 calcium sources for the purpose of corrosion control have been conducted. Removal efficiencies with respect to relevant water quality parameters are presented, with typical relationships between raw water NOM content, coagulant dose requirements and pH. Generally, when applying metal-based coagulants, residual metal concentration was the critical parameter regarding minimum coagulant dose requirements. Typical NOM removal efficiencies were in the range of 75-90% and 40-70% with respect to colour and organic carbon, respectively. Optimum pH conditions for the removal of NOM and/or residual metals do not always coincide with that of turbidity. The experiments also showed that poly-aluminium and ferric chlorides might have some benefits over alum in terms of dose requirements and range of optimum pH values, and that chitosan may be used for colour removal with good results.

Solubility of Niobium(V) under Cementitious Conditions: Importance of Ca-niobate

2004 ◽  
Vol 824 ◽  
Author(s):  
Caterina Talerico ◽  
Michael Ochs ◽  
Eric Giffaut
Keyword(s):  
Solid Phase ◽  
Empirical Relation ◽  
Oxide Phase ◽  
X Ray Diffraction ◽  
Ph Values ◽  
Wide Range ◽  
Ph Conditions ◽  
Predicted Values ◽  
Ph Range ◽  
Good Agreement

AbstractThe solubility of niobium was investigated for Ca and pH conditions relevant for cementequilibrated solutions. For the pH range considered (9.5-13.2), the dissolved Nb concentration decreases with increasing pH. Overall, experiments lead to Nb concentrations between 2·10-5 M and 2·10-9 M. For all pH values, the dissolved Nb concentration also decreases systematically with increasing Ca concentration. X-ray diffraction measurements of selected experiments confirmed the presence of a solid Ca-Nb-oxide phase, with CaNb4O11·8H2O (hochelagaite) being the most likely composition. On the basis of these findings an empirical regression model for the prediction of Nb solubility data as a function of pH and Ca concentration was derived. This empirical relation is consistent with the presence of a solubility limiting Ca-Nb solid phase and permits to predict aqueous Nb solubility values in cementitious environments over a relatively wide range of conditions. Predicted values are in good agreement with independent experimental results.

Electrical and optical properties of well-dispersed MWCNTs/PVA nanocomposites under different pH conditions

2018 ◽  
Vol 32 (4) ◽  
pp. 442-453 ◽  
Author(s):  
Emad AM Farrag ◽  
Rami A Abdel-Rahem ◽  
SS Ibrahim ◽  
Ayman S Ayesh
Keyword(s):  
Room Temperature ◽  
Ph Value ◽  
Poly Vinyl Alcohol ◽  
Electrical And Optical Properties ◽  
Multiwalled Carbon ◽  
Casting Technique ◽  
Ph Values ◽  
Current Voltage ◽  
Optimum Ph ◽  
Ph Conditions

Series of polymer nanocomposites films consisting of pretreated multiwalled carbon nanotubes (PT-MWCNTs) and poly (vinyl alcohol) (PVA) were prepared at room temperature. The MWCNTs were initially pretreated with 1.0 M sulfuric acid (PT-MWCNTs) and then allowed to disperse in aqueous solutions at different pH values (2–14). It was found that the dispersion of the PT-MWCNTs is a pH dependent. The best PT-MWCNTs dispersion was obtained at pH = 10. Films of PT-MWCNTs/PVA, at this optimum pH-value, were then prepared by casting technique at different PT-MWCNTs weight fractions. The resulted PT-MWCNTs/PVA films were characterized through the direct visualization, Fourier transform infrared, and morphology test. Besides, current–voltage and direct current electrical conductivity for PT-MWCNTs/PVA nanocomposites at 60°C showed that the conductivity mechanism was ohmic and the percolation threshold was around 0.8 wt% PT-MWCNTs. Optical results showed that PT-MWCNTs are homogeneously distributed in the neat PVA and optical gap is significantly decreased from 4.40 to 2.96 eV.

Metabolic Activity of Multipotent Mesenchymal Stromal Cells by Means of Moification of Ph-Condition of Incubation and the L-Carnitine Effects

10.12737/2740 ◽  
2013 ◽  
Vol 20 (4) ◽  
pp. 100-102
Author(s):  
Горшков ◽  
A. Gorshkov ◽  
Исаева ◽  
I. Isaeva ◽  
Балашов ◽  
...  
Keyword(s):  
Mesenchymal Stromal Cells ◽  
Metabolic Activity ◽  
Stromal Cells ◽  
Sports Medicine ◽  
Multipotent Mesenchymal Stromal Cells ◽  
Mtt Test ◽  
Ph Values ◽  
Optimum Ph ◽  
Ph Range ◽  
Optimal Effect

Culture of cell lines have been used traditionally to evaluate medicinal cytotoxicity. The aim of this study was to evaluate the effect of L-carnitine on the metabolic activity of multipotent mesenchymal stromal cells. Research methods. The object of the study was the culture of multipotent mesenchymal stromal cells of the 6th passage derived from adipocytes in rat. Cultivation of this cell line was carried out at the optimum pH-condition (7.37) and at the modification of the values (4.0, 5.5 and 9.0). The MTT-test was performed by the method of M. Niks and M.Otto in modification. Results. The research culture of cells, it is shown that the simulation acidosis (pH 4.0 and 5.5) and alkalosis (pH of 9.0) accompanied by a decrease in the intensity of their metabolism by MTT test. The severity of oppression activity of mitochondrial dehydrogenases significantly depended on the magnitude of deviations from normal pH values. Introduction in the environment of cultivation L-carnitine in the range of concentrations 10-3-10-10 Mol/1 increases the intensity of formation of theformazan salts all over the pH range of incubation medium. The optimal effect of L-carnitine manifests in concentrations 10-5-10-6 Mol/1 and with the least deviation of the pH of the environment from the normal values. The discussion. The obtained results confirm the hypothesis about the ability of L-carnitine to maintain the metabolism of cells in the failure of intra - and extracellular pH caused by stress, hypoxia, strenuous and ischemia. In the conditions and acidosis and alkalosis L- carnitine stimulates the synthesis of ATP through participation in the oxidation of free fatty acids into the mitochondria. This property of the drug may explain some of its pharmacological effects and is of interest for specialists in the field of sports medicine.

Conserved amphiphilic feature is essential for periplasmic chaperone HdeA to support acid resistance in enteric bacteria

2008 ◽  
Vol 412 (2) ◽  
pp. 389-397 ◽  
Author(s):  
Ye E. Wu ◽  
Weizhe Hong ◽  
Chong Liu ◽  
Lingqing Zhang ◽  
Zengyi Chang
Keyword(s):  
Pathogenic Bacteria ◽  
Acid Resistance ◽  
Enteric Bacteria ◽  
Structural Features ◽  
Low Ph ◽  
Hydrophobic Region ◽  
Ph Values ◽  
Ph Conditions ◽  
Stomach Ph ◽  
Ph Range

The extremely acidic environment of the mammalian stomach (pH 1–3) represents a stressful challenge for enteric pathogenic bacteria, including Escherichia coli, Shigella and Brucella. The hdeA (hns-dependent expression A) gene was found to be crucial for the survival of these enteric bacteria under extremely low pH conditions. We recently demonstrated that HdeA is able to exhibit chaperone-like activity exclusively within the stomach pH range by transforming from a well-folded conformation at higher pH values (above pH 3) into an unfolded conformation at extremely low pH values (below pH 3). This study was performed to characterize the action mechanisms and underlying specific structural features for HdeA to function in this unfolded conformation. In the present study, we demonstrate that the conserved ‘amphiphilic’ feature of HdeA, i.e. the exposure of the conserved hydrophobic region and highly charged terminal regions, is essential for exhibiting chaperone-like activity under extremely low pH conditions. Mutations that disrupt this amphiphilic feature markedly reduced the chaperone-like activity of HdeA. The results also strongly suggest that this acid-induced chaperone-like activity of HdeA is crucial for acid resistance of the enteric bacteria. Moreover, our new understanding of this amphiphilic structural feature of HdeA helps to better interpret how this unfolded (disordered) conformation could be functionally active.

The Malachite Green Biodegradation in Bioreactors on Various pH Domains

2019 ◽  
Vol 70 (8) ◽  
pp. 2996-2999
Author(s):  
Viorel Gheorghe ◽  
Catalina Gabriela Gheorghe ◽  
Andreea Bondarev ◽  
Vasile Matei ◽  
Mihaela Bombos
Keyword(s):  
Malachite Green ◽  
Contact Time ◽  
Dominant Species ◽  
Wastewater Treatment Plants ◽  
Organic Substances ◽  
Biological Degradation ◽  
Growth Promoters ◽  
Ph Values ◽  
Biological Sludge ◽  
Ph Range

In the experimental study was studied the malachite green colorant biodegradation in biological sludge with biological activity. The biodegradability tests were carried out in laboratory bioreactors, on aqueous solutions of green malachite contacted with microorganisms in which the dominant species is Paramecium caudatum, in a pH range between 8 and 12, temperatures in the ranges 25-350C, using pH neutralizing substances and biomass growth promoters. The colorant initial concentrations and those obtained after biological degradation depending on the contact time, at certain pH values, were established through UV-Vis spectrometry. The studies have shown the measure of possible biological degradation of some organic substances with extended uses, with largely aromatic structure, resistance to biodegradation of microorganisms, commonly used in wastewater treatment plants.

Trans-sialidase Associated with Atherosclerosis: Defining the Identity of a Key Enzyme Involved in the Pathology

2019 ◽  
Vol 20 (9) ◽  
pp. 938-941
Author(s):  
Victor Y. Glanz ◽  
Veronika A. Myasoedova ◽  
Andrey V. Grechko ◽  
Alexander N. Orekhov
Keyword(s):  
Acid Metabolism ◽  
Research Subject ◽  
Disease Pathogenesis ◽  
Sialidase Activity ◽  
Ph Values ◽  
Ldl Particles ◽  
Optimum Ph ◽  
Key Enzyme ◽  
St6gal I

Atherosclerosis is associated with the increased trans-sialidase activity, which can be detected in the blood plasma of atherosclerosis patients. The likely involvement in the disease pathogenesis made this activity an interesting research subject and the enzyme that may perform such activity was isolated and characterized in terms of substrate specificity and enzymatic properties. It was found that the enzyme has distinct optimum pH values, and its activity was enhanced by the presence of Ca2+ ions. Most importantly, the enzyme was able to cause atherogenic modification of lowdensity lipoprotein (LDL) particles in vitro. However, the identity of the discovered enzyme remained to be defined. Currently, sialyltransferases, mainly ST6Gal I, are regarded as major contributors to sialic acid metabolism in human blood. In this mini-review, we discuss the possibility that atherosclerosis- associated trans-sialidase does, in fact, belong to the sialyltransferases family.

scholarly journals Critical importance of pH and collector type on the flotation of sphalerite and galena from a low-grade lead–zinc ore

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Abdolrahim Foroutan ◽  
Majid Abbas Zadeh Haji Abadi ◽  
Yaser Kianinia ◽  
Mahdi Ghadiri
Keyword(s):  
Iron Ore ◽  
Low Grade ◽  
Zinc Recovery ◽  
Flotation Process ◽  
Ph Values ◽  
Lead And Zinc ◽  
Optimum Ph ◽  
Iron And Zinc ◽  
Lead Zinc ◽  
Zinc Concentrate

AbstractCollector type and pulp pH play an important role in the lead–zinc ore flotation process. In the current study, the effect of pulp pH and the collector type parameters on the galena and sphalerite flotation from a complex lead–zinc–iron ore was investigated. The ethyl xanthate and Aero 3418 collectors were used for lead flotation and Aero 3477 and amyl xanthate for zinc flotation. It was found that maximum lead grade could be achieved by using Aero 3418 as collector at pH 8. Also, iron and zinc recoveries and grades were increased in the lead concentrate at lower pH which caused zinc recovery reduction in the zinc concentrate and decrease the lead grade concentrate. Furthermore, the results showed that the maximum zinc grade and recovery of 42.9% and 76.7% were achieved at pH 6 in the presence of Aero 3477 as collector. For both collectors at pH 5, Zinc recovery was increased around 2–3%; however, the iron recovery was also increased at this pH which reduced the zinc concentrate quality. Finally, pH 8 and pH 6 were selected as optimum pH values for lead and zinc flotation circuits, respectively.

Analysis of Whey Proteins Solubility at High Temperatures

2012 ◽  
Vol 8 (3) ◽  
Author(s):  
Daniela Helena Guimarães Pelegrine ◽  
Maria Thereza Moraes Santos Gomes
Keyword(s):  
Heat Exchangers ◽  
Protein Unfolding ◽  
Protein Solubility ◽  
Whey Proteins ◽  
Protein Isolate ◽  
Cow Milk ◽  
Ph Conditions ◽  
Effects Of Temperature ◽  
Ph Range ◽  
Integrated Study

Abstract This work showed the whey proteins solubility curves, according with temperature and pH conditions. The product constituted of a whey protein isolate obtained from cow milk (ALACENTM 895), acquired by New Zeland Milk Products Ltd. There is a straight analogy between fouling and protein unfolding when milk derived fluids are processed in equipments of heat exchangers, where whey proteins are unfolded in an irreversible way, exposing hidrophobic groups, and they become insoluble and form aggregates. An integrated study was conducted on the effects of temperature and pH on the solubility of whey proteins. The solubility was determined experimentally in the temperature range of 40-90 °C, and pH range of 5.0 - 6.8. The results showed that, both the temperature and pH influenced in the protein solubility; besides, the solubility values were minimum at the pH 4.0 for all temperature values. It was also observed that solubility decreased with temperature increased.

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