Stepwise reduction of the culture redox potential allows the analysis of microaerobic metabolism and photosynthetic membrane synthesis inRhodospirillum rubrum

2012 ◽  
Vol 110 (2) ◽  
pp. 573-585 ◽  
Author(s):  
Lisa Carius ◽  
Oliver Hädicke ◽  
Hartmut Grammel
Keyword(s):  
Redox Potential ◽  
Photosynthetic Membrane ◽  
Membrane Synthesis ◽  
Stepwise Reduction ◽  
Culture Redox Potential

Stepwise reduction of samarium cryptates in propylene carbonate: anions and water concentration effects on the redox behavior of the Sm(III)/Sm(II) couple

1988 ◽  
Vol 66 (9) ◽  
pp. 2172-2176 ◽  
Author(s):  
Edouard Laurent Loufouilou ◽  
Jean Paul Gisselbrecht
Keyword(s):  
Redox Potential ◽  
Propylene Carbonate ◽  
Water Concentration ◽  
Oxidation States ◽  
Mixed Complex ◽  
Polarographic Reduction ◽  
Redox Behavior ◽  
Redox Potentials ◽  
Concentration Effects ◽  
Stepwise Reduction

The polarographic reduction of samarium(III) cryptates with cryptands 222, 221, and 22 was investigated in propylene carbonate. The samarium(III) cryptates are reduced in two consecutive steps, the first step was reversible and corresponded to the reduction of the Sm(III) to the Sm(II) cryptate. The Sm(III)/Sm(II) redox potential of the cryptates depended on the anion used in the complex and, in the case of the cryptate with chloride anions, a stable mixed complex was observed in propylene carbonate. The Sm(III)/Sm(II) redox potentials of the cryptates were more cathodic than the redox potential of the uncomplexed Sm(III)/Sm(II) couple, which is typical of a lower stability of the reduced cryptate. Propylene carbonate does not stabilize low oxidation states of lanthanides by cryptation. This is at variance with behavior observed previously in other media like water and methanol. Variations of redox potentials as a function of increasing amounts of water were accounted for by solvent shielding of samarium(III) upon encapsulation in cryptands.

Relationship between culture redox potential and culture fluorescence inCorynebacterium glutamicum

1988 ◽  
Vol 2 (4) ◽  
pp. 233-236 ◽  
Author(s):  
E. L. Winter ◽  
Govind Rao ◽  
T. W. Cadman
Keyword(s):  
Redox Potential ◽  
Culture Redox Potential

scholarly journals Conditions for Vigorous Growth on Sulfide and Reactor-Scale Cultivation Protocols for the Thermophilic Green Sulfur Bacterium Chlorobium tepidum

1999 ◽  
Vol 65 (1) ◽  
pp. 301-306 ◽  
Author(s):  
Biswarup Mukhopadhyay ◽  
Eric F. Johnson ◽  
Manuel Ascano
Keyword(s):  
Redox Potential ◽  
Electron Source ◽  
Chlorobium Tepidum ◽  
Sulfide Concentration ◽  
Optimum Level ◽  
Green Sulfur Bacterium ◽  
The Family ◽  
Culture Redox Potential ◽  
Vigorous Growth ◽  
Green Sulfur

ABSTRACT We describe a reactor-scale cultivation protocol for the fastest-growing and only known thermophilic member of the family Chlorobiaceae, Chlorobium tepidum. We discovered that C. tepidum would grow with sulfide as the sole electron source at rates and with final cell yields comparable to those found with thiosulfate only if the sulfide concentration was maintained below 0.1 mM and the culture redox potential was at −300 ± 20 mV. Such was also the requirement for growth in a photobioreactor when thiosulfate (optimum level, 12 mM) was used as the preferred electron source. For cultivation of C. tepidum on a 5- to 500-ml scale, we used the system of Balch and Wolfe (Appl. Environ. Microbiol. 32:781–791, 1976) using stopper-sealed serum tubes and bottles as an alternative to the methods commonly used for the cultivation of phototrophic anaerobes and obtained consistent results.

Redox potential as a controlling factor in enhancing carbon tetrachloride biodegradation

1996 ◽  
Vol 34 (10) ◽  
pp. 59-66
Author(s):  
G. Jin ◽  
A. J. Englande
Keyword(s):  
Carbon Tetrachloride ◽  
Redox Potential ◽  
Critical Role ◽  
Industrial Effluents ◽  
Cost Effective ◽  
Pseudomonas Cepacia ◽  
Degradation Rate Constant ◽  
Cost Effective Technique ◽  
Culture Redox Potential ◽  
Providencia Stuartii

Biodegradation of hazardous waste is often the most cost-effective technique suitable for purifying large quantities of polluted groundwater and industrial effluents. In an effort of optimizing environmental conditions for microorganisms to degrade carbon tetrachloride, culture redox potential (Eh) was demonstrated as having a critical role. The microorganisms tested were isolated from contaminated field sites and included Pseudomonas cepacia and Providencia stuartii. Ti(III) citrate was used as a reducing agent to poise Eh at designed values. Over 99% degradation of carbon tetrachloride was effected in 3 days at −250 mV ≤ Eh ≤ −200 mV. Lesser rates were observed at Eh ≥ 0 mV. Kinetic analysis indicated that the overall degradation rate constant increased from 2.75×10−3 h−1 to 4.75×10−2 h−1 by controlling Eh at about −200 mV compared with Eh at ≥ 0 mV. Results indicated that the implementation of critical redox potential may be effective in optimizing CT biodegradation activity.

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