Inhibition of lysozyme aggregation and cellular toxicity by organic acids at acidic and physiological pH conditions

The electrokinetic remediation of an agricultural soil contaminated with heavy metals was studied using organic acids as facilitating agents. The unenhanced electrokinetic treatment using deionized water as processing fluid did not show any significant mobilization and removal of heavy metals due to the low solubilization of metals and precipitation at high pH conditions close to the cathode. EDTA and citric acid 0.1 M were used as facilitating agents to favor the dissolution and transportation of metals. The organic acids were added to the catholyte and penetrated into the soil specimen by electromigration. EDTA formed negatively charged complexes. Citric acid formed neutral metal complexes in the soil pH conditions (pH = 2–4). Citric acid was much more effective in the dissolution and transportation out of the soil specimen of complexed metals. In order to enhance the removal of metals, the concentration of citric acid was increased up to 0.5 M, resulting in the removal of 78.7% of Cd, 78.6% of Co, 72.5% of Cu, 73.3% of Zn, 11.8% of Cr and 9.8% of Pb.

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Transcriptional profiling reveals molecular basis and the role of arginine in response to low-pH stress in Pichia kudriavzevii

10.21203/rs.2.18639/v1 ◽

2019 ◽

Author(s):

Hao Ji ◽

Xiameng Dong ◽

Kailun Zhang ◽

Libo Jin ◽

Renyi Peng ◽

...

Keyword(s):

Organic Acids ◽

Molecular Basis ◽

Transcriptional Profiling ◽

Cell Aggregation ◽

Membrane Lipid ◽

Low Ph ◽

Pichia Kudriavzevii ◽

Ph Stress ◽

Ph Conditions

Abstract BackgroundThe non-conventional yeast Pichia kudriavzevii possesses a unique ability to tolerate various environmental stresses particularly low-pH stress. Thus, it is considered to be a promising biotechnological host for the production of various organic acids under low-pH conditions. However, little is known about the low-pH stress response in P. kudriavzevii, which significantly restricts its future development. ResultsIn this study, P. kudriavzevii JLY1107 showed great tolerance to low-pH stress, but its cell aggregation upon acidic conditions is unfavorable for the development of low-pH fermentation. To explore the molecular basis, we conducted RNA-Seq to compare global gene expression in response to low-pH. Among the 429 differentially expressed genes, the genes associated with regulation of membrane lipid composition, filamentous growth and arginine metabolism were selected for in-depth discussions. The up-regulation of genes associated with arginine uptake and degradation suggests a potential role of arginine in response to low-pH strsss. We therefore present data supporting the hypothesis that P. kudriavzevii maintains intracellular homeostasis by using the ammonia produced by arginine catabolism. Furthermore, external addition of arginine significantly enhances growth and reduces cell aggregation of P. kudriavzevii under low-pH conditions.ConclusionsArginine was demonstrated to be a promising molecule for improving cell growth and preventing cell aggregation under extremely low-pH conditions. Our study is a step towards developing the non-conventional yeast P. kudriavzevii as a platform host for the production of organic acids under low-pH conditions.

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Solubility of Iron in Model Systems Containing Organic Acids and Lignin

Journal of Food Protection ◽

10.4315/0362-028x-55.11.893 ◽

1992 ◽

Vol 55 (11) ◽

pp. 893-898 ◽

Cited By ~ 13

Author(s):

TAKESHI SUZUKI ◽

FERGUS M. CLYDESDALE ◽

TIRA PANDOLF

Keyword(s):

Ascorbic Acid ◽

Organic Acids ◽

Model Systems ◽

Molar Ratio ◽

Soluble Form ◽

Enhancing Effect ◽

Gastrointestinal Ph ◽

Soluble Iron ◽

Ph Values ◽

Ph Conditions

The effect of six organic acids, ascorbic, citric, fumaric, lactic, malic, and succinic, alone and in combination, at a 1:1.9 molar ratio (Fe+2:ligand) on the solubility of iron was evaluated in the presence of lignin under simulated gastrointestinal pH conditions. The enhancing effect, evaluated under two systems of preparation at two pH values, was in the following order: citric>malic>ascorbic>lactic,fumaric>succinic. Citric acid solubilized 80 and 81% of iron under both pH conditions. When ascorbic acid was mixed with fumaric, lactic, and succinic acids, a higher percentage of soluble iron was retained than with these three acids alone. In the case of citric and malic acids, the addition of ascorbic acid reduced the soluble iron. The percentage of soluble iron obtained when prepared at the endogenous pH (2.5–3.1) was higher than that at pH 5.5. These results indicated that ascorbate bound less iron in a soluble form than citrate or malate but more than fumarate, lactate, or succinate. Also, combinations of citric with malic acid did not demonstrate a synergistic effect.

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Effects of Microorganisms Growth on the Long-Term Stability of Cement and Bitumen

MRS Proceedings ◽

10.1557/proc-294-267 ◽

1992 ◽

Vol 294 ◽

Cited By ~ 2

Author(s):

Marie F. Libert ◽

R. Sellier ◽

G. Jouquet ◽

M. Trescinski ◽

H. Spor

Keyword(s):

Organic Acids ◽

Nuclear Waste ◽

Long Term Stability ◽

Mineral Acids ◽

Ph Conditions ◽

Waste Repositories ◽

Coating Matrix ◽

Geological Formations ◽

Growth Of Fungi

ABSTRACTCement is used as a coating matrix for nuclear waste or as an engineered barrier of waste repositories situated in geological formations.The effect of mineral acids excreted by bacteria (Thiobacillus) or organic acids produced by fungi, on the biodegradation of cement is discussed. Organic acids are quantitatively and qualitatively determined during growth of fungi over a two-year period. Even with high pH conditions, pH of the cement ≈ 11, growth of microorganisms occurs.Biodeterioration of cement is expressed in terms of bioleaching velocity of calcium and is observed by electron microscopy.

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Photo-Oxidation of cis-Pinic Acid in the Aqueous Phase: A Mechanistic Investigation Under Acidic and Basic pH Conditions

Environmental Science: Atmospheres ◽

10.1039/d1ea00031d ◽

2021 ◽

Author(s):

Jéssica Vejdani Amorim ◽

Xinyang Guo ◽

Tania Gautam ◽

Rongyan Fang ◽

Christian Fotang ◽

...

Keyword(s):

Organic Acids ◽

Aqueous Phase ◽

Liquid Water ◽

Water Soluble ◽

Photo Oxidation ◽

Mechanistic Investigation ◽

Ph Conditions ◽

Reaction Media ◽

Pinic Acid

Atmospheric aqueous phases (cloud and fog droplets, aerosol liquid water) are important reaction media for the processing of water-soluble organic acids (OAs). The photochemistry of these species is known to...

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