The effect of low oxygen uptake rate on the fatty acid profile of the oleaginous yeast Apiotrichum curvatum

1990 ◽  
Vol 33 (5) ◽  
Author(s):  
R.Julian Davies ◽  
JaneE. Holdsworth ◽  
SarahL. Reader
Keyword(s):  
Fatty Acid ◽  
Oxygen Uptake ◽  
Fatty Acid Profile ◽  
Uptake Rate ◽  
Oleaginous Yeast ◽  
Oxygen Uptake Rate ◽  
Low Oxygen ◽  
Apiotrichum Curvatum

Optimum aerobic volume control based on continuous in-line oxygen uptake monitoring

2003 ◽  
Vol 47 (11) ◽  
pp. 305-312 ◽  
Author(s):  
K. Svardal ◽  
S. Lindtner ◽  
S. Winkler
Keyword(s):  
Oxygen Uptake ◽  
Uptake Rate ◽  
Oxygen Uptake Rate ◽  
Air Flow ◽  
Volume Control ◽  
Ammonium Concentration ◽  
Aeration Tank ◽  
Low Oxygen ◽  
Control Concept ◽  
Line Oxygen

Dynamic adaptation of the aerated volume to changing load conditions is essential to maximise the nitrogen removal performance and to minimise energy consumption. A control strategy is presented which provides optimum aerobic volume control (OAV-control concept) based on continuous in-line oxygen uptake monitoring. For ammonium concentrations below 1 mg/l the oxygen uptake rate shows a strong and almost linear dependency on the ammonium concentration. Therefore, the oxygen uptake rate is an ideal indicator for the nitrification performance in activated sludge systems. The OAV-control concept provides dynamic variation of the minimum aerobic volume required for complete nitrification and therefore maximises the denitrification performance. In-line oxygen uptake monitoring is carried out by controlling the oxygen concentration in a continuous aerated zone of the aeration tank and measuring the total air flow to the aeration tank. The total air flow to the aeration tank is directly proportional to the current oxygen uptake rate and can therefore be used as an indicator for the required aerobic volume. The instrumentation requirements for installation of the OAV-control are relatively low, oxygen sensors in the aeration tank and an on-line air flow measurement are needed. This enables individual control of aeration tanks operated in parallel at low investment costs. The OAV-control concept is installed at the WWTP Linz-Asten (1 Mio PE) and shows very good results. Full scale results are presented.

A Device to Measure the Oxygen Uptake Rate of Attached Cells: Importance in Bioartificial Organ Design

1994 ◽  
Vol 3 (6) ◽  
pp. 515-527 ◽  
Author(s):  
Brent D. Foy ◽  
Avi Rotem ◽  
Mehmet Toner ◽  
Ronald G. Tompkins ◽  
Martin L. Yarmush
Keyword(s):  
Oxygen Uptake ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Uptake Rate ◽  
Oxygen Uptake Rate ◽  
Collagen Gel ◽  
Matrix Composition ◽  
Bottom Surface ◽  
Low Oxygen ◽  
Culture Dish

Quantification of the dependence of cellular oxygen uptake rate (OUR) on oxygen partial pressure is useful for the design and testing of bioartificial devices which utilize cells. Thus far, this information has only been obtained from suspended cells and from cells attached to microcarriers. In this work, a device was developed to obtain the dependence of OUR on oxygen partial pressure for anchorage-dependent cells cultured in standard culture dishes. The device is placed and sealed on the top of the culture dish, and holds a Clark polarographic mini-electrode flush with the bottom surface of the device. It also houses a motor to spin a magnetic stir bar within the cell chamber to insure that the medium is well-mixed. Several characteristics of the device — such as oxygen leakage into the device chamber, electrode-lag time, and linearity of the electrode at low oxygen partial pressures-were quantified and their potential effect on the values of Vm (maximal OUR) and K0.5 (oxygen partial pressure at which OUR is half-maximal) were evaluated. Comparison of Vm and K0.5 values obtained with this device with previously published values for suspended rat hepatocytes, Bacillus cereus, and E. coli indicated that the technique provides values accurate within 30% as long as the cell under study has a K0.5 greater than approximately 1.0 mmHg. For hepatocytes cultured on 0.05 mm thickness collagen gel for 1 day (n = 4) and 3 days (n = 6), Vm was found to be 0.38 ± 0.12 and 0.25 ± 0.09 nmol O2/s/106 cells, respectively, and K0.5 was found to be 5.6 ± 0.5 and 3.3 ± 0.6 mmHg, respectively. This technique should aid in predicting bioreactor conditions such as flow rate, cell density, distance of cell from flow, and gas phase oxygen partial pressure which can lead to oxygen limitations. In addition, further studies of the effect of factors such as extracellular matrix composition, metabolic substrate, and drugs on the dependence of OUR on oxygen partial pressure for many anchorage-dependent cell types can be pursued with this technique.

Exposure to degraded coral habitat depresses oxygen uptake rate during exercise of a juvenile reef fish

Coral Reefs ◽  
2021 ◽  
Author(s):  
Adam T. Downie ◽  
Caroline M. Phelps ◽  
Rhondda Jones ◽  
Jodie L. Rummer ◽  
Douglas P. Chivers ◽  
...  
Keyword(s):  
Oxygen Uptake ◽  
Reef Fish ◽  
Uptake Rate ◽  
Oxygen Uptake Rate ◽  
Juvenile Reef Fish

Mass transfer impacts in flocculent and granular biomass from SBR systems

2004 ◽  
Vol 50 (10) ◽  
pp. 203-212 ◽  
Author(s):  
D. Gapes ◽  
B.-M. Wilén ◽  
J. Keller
Keyword(s):  
Mass Transfer ◽  
Particle Size ◽  
Oxygen Uptake ◽  
Activated Sludge ◽  
Uptake Rate ◽  
Oxygen Uptake Rate ◽  
Batch Reactor ◽  
Average Particle Size ◽  
Gas Analysis ◽  
Average Particle

An experimental study was conducted to describe mass transfer impacts within nitrifying aggregates sourced from sequencing batch reactor (SBR) activated sludge systems. Flocculent and granular sludge with high nitrification activity was obtained in two laboratory SBR systems, supplied with a synthetic, ammonium-based feed. The flocculent biomass was fractionated using a sieving procedure, in order to obtain biomass fractions with different particle size distributions. The oxygen uptake rate (OUR) response to changes in dissolved oxygen concentration was measured under highly controlled conditions in a titrimetric and off-gas analysis (TOGA) sensor, and the results used to assess mass transfer effects. As the average particle size of the biomass increased, mass transfer limitations were found to increase significantly. Empirically fitted, apparent KS,O2 values were demonstrated to be highly dependent on particle size, and reflect the mass transfer limitations occurring in the aggregates within a given system. Such parameters thus have little to do with the actual biokinetic parameter from which they are derived. The results obtained from the TOGA sensor study were consistent with those obtained from a microelectrode study on the same nitrifying granules. Together, these studies add considerable weight to the conclusion that consideration of external and internal mass transfer limitations is vital to the accurate description of activated sludge treatment processes, particularly those with a high oxygen uptake rate.

Disturbance observer for estimation of oxygen uptake rate in an activated sludge reactor

2016 ◽  
Author(s):  
Francisco Jadilson dos Santos Silva ◽  
Euler C. T. de Macedo ◽  
Sebastian Y. C. Catunda ◽  
Carlos E. T. Dorea ◽  
Adrianus C. Van Haandel
Keyword(s):  
Oxygen Uptake ◽  
Activated Sludge ◽  
Uptake Rate ◽  
Disturbance Observer ◽  
Oxygen Uptake Rate ◽  
Activated Sludge Reactor
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