Removal of Anionic Metalloid/Metals by PEI-Modified Corynebacterium glutamicum

2013 ◽  
Vol 825 ◽  
pp. 568-571
Author(s):  
Namgyu Kim ◽  
Munsik Park ◽  
Jongmoon Park ◽  
Donghee Park
Keyword(s):  
Aqueous Solution ◽  
Binding Site ◽  
Corynebacterium Glutamicum ◽  
Adsorption Mechanism ◽  
Competitive Inhibition ◽  
Aqueous System ◽  
Reduction Mechanism ◽  
Removal Mechanism ◽  
Sulfate Ion ◽  
Industrial Fermentation

An anionic biosorbent was derived from an industrial fermentation biowate, Corynebacterium glutamicum, by being cross-linked with polyethylenimine (PEI). A fiber form of the biosorbent was used to examine its potentiality of removing anionic metals such as As (V), Cr (VI) and Mn (VII) in aqueous system. As (V) and Cr (VI) were efficiently removed by the biosorbent through anionic adsorption mechanism. Sulfate ion seriously inhibited adsorption of the anionic metals through competitive inhibition with respect to the binding site of the biosorbent. In the case of Mn (VII), its removal mechanism by the biosorbent was not anionic adsorption. Mn (VII) was completely removed in aqueous phase, meanwhile, Mn (II) appeared and increased in proportion to the Mn (VII) depletion. As a result, adsorption coupled reduction was chosen as the mechanism of Mn (VII) removal by the biosorbent. In conclusion, the anionic biosorbent could be used to remove various anionic metals from aqueous solution through anionic adsorption or reduction mechanism.

scholarly journals The ldhA Gene Encoding Fermentative L-Lactate Dehydrogenase in Corynebacterium glutamicum Is Positively Regulated by the Global Regulator GlxR

2021 ◽  
Vol 9 (3) ◽  
pp. 550
Author(s):  
Koichi Toyoda ◽  
Masayuki Inui
Keyword(s):  
Lactate Dehydrogenase ◽  
Binding Site ◽  
Corynebacterium Glutamicum ◽  
Lactate Production ◽  
Exponential Phase ◽  
Aerobic Bacterium ◽  
Global Regulator ◽  
Gene Encoding ◽  
Fermentation Products ◽  
Ldha Gene

Bacterial metabolism shifts from aerobic respiration to fermentation at the transition from exponential to stationary growth phases in response to limited oxygen availability. Corynebacterium glutamicum, a Gram-positive, facultative aerobic bacterium used for industrial amino acid production, excretes L-lactate, acetate, and succinate as fermentation products. The ldhA gene encoding L-lactate dehydrogenase is solely responsible for L-lactate production. Its expression is repressed at the exponential phase and prominently induced at the transition phase. ldhA is transcriptionally repressed by the sugar-phosphate-responsive regulator SugR and L-lactate-responsive regulator LldR. Although ldhA expression is derepressed even at the exponential phase in the sugR and lldR double deletion mutant, a further increase in its expression is still observed at the stationary phase, implicating the action of additional transcription regulators. In this study, involvement of the cAMP receptor protein-type global regulator GlxR in the regulation of ldhA expression was investigated. The GlxR-binding site found in the ldhA promoter was modified to inhibit or enhance binding of GlxR. The ldhA promoter activity and expression of ldhA were altered in proportion to the binding affinity of GlxR. Similarly, L-lactate production was also affected by the binding site modification. Thus, GlxR was demonstrated to act as a transcriptional activator of ldhA.

Structure and water exchange of the hydrated thiosulfate ion in aqueous solution using QMCF MD simulation and large angle X-ray scattering

2014 ◽  
Vol 43 (33) ◽  
pp. 12711-12720 ◽  
Author(s):  
Lars Eklund ◽  
Tomas S. Hofer ◽  
Alexander K. H. Weiss ◽  
Andreas O. Tirler ◽  
Ingmar Persson
Keyword(s):  
Aqueous Solution ◽  
Sulfur Atom ◽  
Md Simulation ◽  
Water Exchange ◽  
Large Angle ◽  
Sulfate Ion ◽  
Simulation Data ◽  
X Ray ◽  
X Ray Scattering ◽  
Hydration Structure

Experimental and simulation data of the thiosulfate ion show large similarities in hydration structure and mechanism with the sulfate ion but with weaker hydration of the terminal sulfur atom in thiosulfate.

Dispersion of TiO2 Nanoparticles in Aqueous Solution

2018 ◽  
Vol 922 ◽  
pp. 8-13
Author(s):  
Wen Xiu Liu ◽  
Peng Sun ◽  
Jun Zhang ◽  
Wen Bin Cao
Keyword(s):  
Aqueous Solution ◽  
Particle Size ◽  
Mass Fraction ◽  
Adsorption Mechanism ◽  
Secondary Particle ◽  
Aqueous Dispersion ◽  
Ftir Analysis ◽  
Carboxylate Groups ◽  
The Stability ◽  
Potential Test

Stable TiO2aqueous dispersion with an averaged secondary particle size of about 10 nm was achieved by using commercially available dispersant Di-7N. The stability of the dispersion was measured by Zeta-potential test. And the results showed that the optimal mass fraction of Di-7N was 12 wt%. The adsorption mechanism examined by FTIR analysis indicates that the carboxylate groups in Di-7N is absorbed on the surface of nano-TiO2particles and the adsorbed structure is proposed to be bidentate chelating.

Pb(II) adsorption mechanism and capability from aqueous solution using red mud modified by chitosan

Chemosphere ◽  
2022 ◽  
Vol 287 ◽  
pp. 132279
Author(s):  
Thi-Thuy Luu ◽  
Van-Phuc Dinh ◽  
Quang-Hung Nguyen ◽  
Ngoc-Quyen Tran ◽  
Duy-Khoi Nguyen ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Red Mud ◽  
Adsorption Mechanism

Competitive Inhibition of Quercetin and Apigenin at the ATP Binding site of D-Alanine-D-Alanine Ligase of Helicobacter pylori – A Molecular Modeling Approach

2019 ◽  
Vol 7 (5) ◽  
pp. 340-348 ◽  
Author(s):  
Salam Pradeep Singh ◽  
Chandrabose Selvaraj ◽  
Bolin Kumar Knowar ◽  
Sanjeev Kumar Singh ◽  
Chingakham Brajakishor Singh ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Molecular Modeling ◽  
Binding Site ◽  
Competitive Inhibition ◽  
Atp Binding ◽  
Atp Binding Site ◽  
Modeling Approach
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