On-line assessment of metabolic activities based on culture redox potential and dissolved oxygen profiles during aerobic fermentation

1992 ◽  
Vol 8 (6) ◽  
pp. 576-579 ◽  
Author(s):  
Simon C. W. Kwong ◽  
Lisa Randers ◽  
Govind Rao
Keyword(s):  
Dissolved Oxygen ◽  
Redox Potential ◽  
Aerobic Fermentation ◽  
Culture Redox Potential ◽  
On Line ◽  
Metabolic Activities ◽  
Oxygen Profiles

Automated sequencing batch bioreactor under extreme peaks of 4-chlorophenol

2003 ◽  
Vol 47 (10) ◽  
pp. 175-181 ◽  
Author(s):  
G. Buitrón ◽  
M.-E. Schoeb ◽  
J. Moreno
Keyword(s):  
Dissolved Oxygen ◽  
Metabolic Activity ◽  
Automated System ◽  
Stable Operation ◽  
High Concentration ◽  
Batch Bioreactor ◽  
On Line ◽  
The Moment ◽  
And Control ◽  
System Operating

The operation of a sequencing batch bioreactor is evaluated when high concentration peaks of a toxic compound (4-chlorophenol, 4CP) are introduced into the reactor. A control strategy based on the dissolved oxygen concentration, measured on line, is utilized. To detect the end of the reaction period, the automated system search for the moment when the dissolved oxygen has passed by a minimum, as a consequence of the metabolic activity of the microorganisms and right after to a maximum due to the saturation of the water (similar to the self-cycling fermentation, SCF, strategy). The dissolved oxygen signal was sent to a personal computer via data acquisition and control using MATLAB and the SIMULINK package. The system operating under the automated strategy presented a stable operation when the acclimated microorganisms (to an initial concentration of 350 mg 4CP/L), were exposed to a punctual concentration peaks of 600 mg 4CP/L. The 4CP concentrations peaks superior or equals to 1,050 mg/L only disturbed the system from a short to a medium term (one month). The 1,400 mg/L peak caused a shutdown in the metabolic activity of the microorganisms that led to the reactor failure. The biomass acclimated with the SCF strategy can partially support the variations of the toxic influent since, at the moment in which the influent become inhibitory, there is a failure of the system.

Effect of controlled redox potential and dissolved oxygen on the in vitro refolding of an E. coli alkaline phosphatase and chicken lysozyme

2013 ◽  
Vol 52 (6-7) ◽  
pp. 312-318 ◽  
Author(s):  
Angélica Meneses-Acosta ◽  
Luis Rodolfo Vizcaíno-Meza ◽  
Hector G. Ayala-Castro ◽  
Martha A. Contreras ◽  
Jaime Ortega-López ◽  
...  
Keyword(s):  
Alkaline Phosphatase ◽  
Dissolved Oxygen ◽  
Redox Potential ◽  
E Coli ◽  
In Vitro Refolding ◽  
Chicken Lysozyme

scholarly journals Characterization of the Effects of Redox Condition on Fe(III)/Fe(II) Transformation in a Small Karstic Aquifer: Poocher Swamp Freshwater Lens, South Australia

2016 ◽  
Vol 6 (3) ◽  
pp. 134 ◽  
Author(s):  
Nara Somaratne
Keyword(s):  
Dissolved Oxygen ◽  
Water Supply ◽  
Redox Potential ◽  
Potable Water ◽  
South Australia ◽  
Redox Conditions ◽  
Geochemical Evolution ◽  
Anoxic Zone ◽  
Freshwater Lens ◽  
Potable Water Supply

<p class="1Body">The presence of iron in potable water supply aquifers poses a major water quality problem and may render the supply unsuitable for domestic or industrial uses, unless appropriate treatments is undertaken. Evaluation of redox conditions in groundwater is a prerequisite for studies involving Fe(III)/Fe(II) transformation in aquifers. This study characterizes the redox conditions, geochemical evolution and distribution of iron in a small karstic freshwater aquifer, the Poocher Swamp freshwater lens, located in south-east of South Australia. The freshwater lens is formed as a result of flows from Tatiara Creek that enter Poocher Swamp and recharge the aquifer through two sinkholes located in the northwest section of the swamp. Stable isotopes of water molecules, δ<sup>2</sup>H<em> </em>and δ<sup>18</sup>O, indicate that both Tatiara Creek and Poocher Swamp waters are isotopically more enriched due to evaporation than the pristine water of the aquifer. The Na<sup>+</sup>/Cl<sup>-</sup> ion ratio &gt;0.85 for Tatiara Creek, Poocher Swamp and wells within the lens suggest additional sodium source(s) are involved in the evolution of groundwater chemistry. This study use redox potential, dissolved oxygen (DO) and dissolved organic carbon (DOC) contents to describe Fe(III)/Fe(II) transformation in the groundwater, and relate this to iron distribution within the lens. Three distinct redox zones are present in the freshwater lens; anoxic zone up to one kilometre from Poocher Swamp where dissolved oxygen (DO)  is &lt;1 mg.L<sup>-1</sup>, redox potential (Eh) &lt;100 mV, and iron (Fe) in groundwater 2.3-9.3 mgL<sup>-1</sup>. Following the anoxic zone is the suboxic zone (from 1to1.5 km from Poocher Swamp), where DO is &lt;1 mg.L<sup>-1</sup>, Eh is about 110-275 mV and Fe is 0.4-0.6 mg.L<sup>-1</sup>. The oxic zone is 1.5 to 2.3 km from Poocher Swamp and is characterized by high DO (2-4 mg.L<sup>-1</sup>), higher Eh (&gt;300 mV) and low in Fe (&lt;0.015 mg.L<sup>-1</sup>). Only 0.4 km<sup>2</sup> of the 13 km<sup>2</sup> area of the freshwater lens is oxygenated, thus limiting further developments of the lens as potable water supply source.</p>

Aeration control on a nitrifying biofilter system by using on-line analyzers

2000 ◽  
Vol 41 (4-5) ◽  
pp. 369-374
Author(s):  
N. Puznava ◽  
D. Thornberg ◽  
P. Magnin ◽  
E. Reddet
Keyword(s):  
Process Control ◽  
Dissolved Oxygen ◽  
Large Scale ◽  
Air Flow ◽  
Ammonia Concentration ◽  
Effluent Quality ◽  
Operation Costs ◽  
New Process ◽  
On Line ◽  
Rainy Days

Two new ways of controlling the aeration in nitrifying biofilters, by measuring on-line dissolved oxygen and ammonia concentration in the effluent of the filter, are compared to the standard control using time tables with constant air flow. Both on pilot and large scale, the new process control concepts proved to be very efficient in optimizing operation costs for aeration (up to 70% during rainy days) and to guarantee a demanded effluent quality.

Transcriptome analysis of Lactococcus lactis subsp. lactis during milk acidification as affected by dissolved oxygen and the redox potential

2016 ◽  
Vol 226 ◽  
pp. 5-12 ◽  
Author(s):  
Nadja Larsen ◽  
Saloomeh Moslehi-Jenabian ◽  
Birgit Brøsted Werner ◽  
Maiken Lund Jensen ◽  
Christel Garrigues ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Redox Potential ◽  
Lactococcus Lactis ◽  
Transcriptome Analysis ◽  
Lactococcus Lactis Subsp
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