Influence of So/Xo Ratio on Anaerobic Activity Test

1999 ◽  
Vol 40 (8) ◽  
pp. 9-15 ◽  
Author(s):  
Gloria Moreno ◽  
Arturo Cruz ◽  
Germán Buitrón
Keyword(s):  
Substrate Concentration ◽  
Reaction Rate ◽  
Biomass Concentration ◽  
Sole Source ◽  
Yield Coefficient ◽  
Initial Biomass Concentration ◽  
Activity Test ◽  
Initial Substrate ◽  
Kinetic Coefficients ◽  
Initial Substrate Concentration

The effect of the substrate/microorganism ratio during the development of anaerobic activity test was studied. The experimentation was carried out in serum bottles at 35°C. Two sets of experiments utilizing acetate and an azo dye (blue disperse 79) as the sole source of carbon were studied. It was observed that mixing has an important influence on the results. The initial substrate concentration and the initial biomass concentration had a significant effect on the reaction rate and on the biomass yield coefficient, Yobs. Different kinetic coefficients were found for the case of equal So/Xo ratio, but different initial substrate concentration.

Determination of the Maintenance Requirements of Activated Sludge

1993 ◽  
Vol 28 (7) ◽  
pp. 139-142 ◽  
Author(s):  
J. Chang ◽  
P. Chudoba ◽  
B. Capdeville
Keyword(s):  
Wastewater Treatment ◽  
Process Development ◽  
Biomass Concentration ◽  
Growth Yield ◽  
Kinetic Studies ◽  
Initial Biomass Concentration ◽  
Aerobic Wastewater Treatment ◽  
Initial Substrate ◽  
Maintenance Requirements ◽  
The Cost

Maintenance energy plays an important role both in basic kinetic studies and in process development. Numerous studies have been devoted to the maintenance concept in various microbial fields but very few in biological wastewater treatment. Using a fermenter coupled to a mass spectrometer, we investigated the influence of the ratio So/Xo (ratio between initial substrate concentration and initial biomass concentration) on the observed sludge growth yield of an oxic-settling anaerobic (OSA) system. By measuring the substrate removed, the oxygen consumed and the carbon dioxide produced, we were able to estimate the substrate fraction used for maintenance purposes. The results indicate that at a high So/Xo ratio, a greater proportion of the substrate is devoted to maintenance thus significantly decreasing the observed growth yield. These findings are of particular importance in view of the cost associated with the disposal of excess sludge in aerobic wastewater treatment processes.

Influence of the initial substrate to microorganisms concentration ratio on the methanogenic inhibition test

2003 ◽  
Vol 48 (6) ◽  
pp. 17-22 ◽  
Author(s):  
I. Moreno-Andrade ◽  
G. Buitrón
Keyword(s):  
Methane Production ◽  
Concentration Ratio ◽  
Suspended Solids ◽  
Great Influence ◽  
Biomass Concentration ◽  
Inhibition Test ◽  
Initial Concentration ◽  
Initial Biomass Concentration ◽  
Initial Substrate

The influence of the initial substrate to microorganisms ratio (So/Xo) on the inhibition of the methane production caused by 4-chlorophenol, 4CP, was studied. The effect of the 4CP on glucose degradation was evaluated measuring the quantity of methane produced during the test. One part of the inoculum was used as it came from its origin and another was fed with ethanol in order to maintain its activity. The inhibition tests were carried out using the same initial concentration of glucose, three initial suspended solids concentrations and eight initial concentrations of 4CP. The use of ethanol-acclimatized sludge presented a great influence on the inhibition results, since the inhibition was greater in the raw sludge than the acclimated one. Significant differences in the inhibition tests were found depending on the initial So/Xo ratio with respect to the glucose as substrate. It was observed that the inhibition decreases as the So/Xo decreases, in other words as the initial biomass concentration increases. When the results were analyzed in respect to the 4CP it was observed that the inhibition increases as the So/Xo increases. Also, it was observed that for the same value of So/Xo there is an increase of the inhibition when the quantity of Xo decreases.

Explanation of Biological Meaning of the So/Xo Ratio in Batch Cultivation

1992 ◽  
Vol 26 (3-4) ◽  
pp. 743-751 ◽  
Author(s):  
P. Chudoba ◽  
B. Capdeville ◽  
J. Chudoba
Keyword(s):  
Mixed Culture ◽  
Biomass Concentration ◽  
Batch Cultivation ◽  
Kinetic Constants ◽  
Cell Multiplication ◽  
Waste Products ◽  
Substrate Removal ◽  
Initial Biomass Concentration ◽  
Initial Substrate ◽  
Exogenous Substrate

It is shown that the most important parameter in batch cultivation of mixed cultures is the ratio of the initial substrate concentration to the initial biomass concentration (So/Xo as COD/biomass). When the ratio is sufficiently low (below 2-4 depending on the mixed culture history) no cell multiplication takes place during the exogenous substrate removal. Under these conditions, a biomass increase is mostly due to the synthesis of storage polymers. It is also shown that the observed yield, Yobs, decreases with increasing So/Xo ratio. Under the high So/Xo conditions, more energy is spent for cell multiplication, which results in greater part of substrate being oxidized. Batch cultivation at high So/Xo ratios results also in higher concentrations of microbial polymers produced as waste products of mixed culture microorganisms. It is concluded that for the biodegradation studies with the aim to obtain kinetic constants it is necessary to work at low So/Xo ratios to prevent mixed culture microorganisms from substantial multiplication. This is necessary because cell multiplication during batch cultivation of mixed culture changes the proportion among slow-growers and fast-growers. This is the only way to obtain the kinetic constants which are representative of the original mixed culture.

scholarly journals The effect of systematic error on the accuracy of Michaelis constants and maximum velocities estimated by using the integrated Michaelis–Menten equation (Short Communication)

1974 ◽  
Vol 143 (3) ◽  
pp. 779-781 ◽  
Author(s):  
Peter F. J. Newman ◽  
Gordon L. Atkins ◽  
Ian A. Nimmo
Keyword(s):  
Reaction Time ◽  
Systematic Error ◽  
Substrate Concentration ◽  
Unknown Parameter ◽  
Short Communication ◽  
Systematic Errors ◽  
Product Concentration ◽  
Initial Substrate ◽  
Michaelis Constants ◽  
Initial Substrate Concentration

Systematic errors in initial substrate concentration (s0), product concentration and reaction time give much larger errors in the Michaelis–Menten parameters unless s0 is treated as an unknown parameter. These errors are difficult to detect because the fitted curve deviates little from the data. The effect of non-enzymic reaction is also examined.

scholarly journals Evaluating the Performance of Three Chambers Microbial Salinity Cell (MSC) Subjected to Different Substrate Concentrations to Accomplish Simultaneous Organic and Salt Removal in the Wastewater

2020 ◽  
Vol 11 (1) ◽  
pp. 19-26
Author(s):  
Rustiana Yuliasni ◽  
Nur Zen ◽  
Nanik Indah Setianingsih
Keyword(s):  
Substrate Concentration ◽  
Carbon Cloth ◽  
Anode Chamber ◽  
Initial Substrate ◽  
Conductivity Increase ◽  
Maximum Current ◽  
Maximum Conductivity ◽  
Vulcan Carbon ◽  
Substrate Concentrations ◽  
Initial Substrate Concentration

This study aimed to identify the effect of substrate concentration on the performance of A Three chambers Microbial Salinity Cell (a three chambers MSC). In this study, 3 three chambers MSC was made of plexy glass with total volume of 200 ml.  Alumunium wrapped with with platinum on vulcan carbon cloth were used as electrodes,with each working area 63 cm2. The results showed that a Three chambers Microbial Salinity Cell was able to generate electricity and at the same time removed salinity. The degree of electricity deneration and salinity removal were influenced by initial substrate concentration in the anode chamber. The higher substrate concentration, the better performance of MSC. The best performance of MSC achieved when COD was 2034 mg/L, resulted in maximum  voltage of 0. 44 V, and  maximum current density of 0.29 mA/m2. With % CE was 5.4%. The maximum conductivity increase in salinity chamber was  from 11.2 µS/cm  to 1027 µS/cm (salinity 0.57% ppt).

Synthesis of (S)-Tert-Butyl 3-Hydroxybutyrate by Asymmetric Reduction of Tert-Butyl Acetoacetate with Saccharomyces cerevisiae B5

2013 ◽  
Vol 704 ◽  
pp. 12-17
Author(s):  
Zhi Min Ou ◽  
Wen Fei Feng ◽  
Li Xu
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Substrate Concentration ◽  
Asymmetric Reduction ◽  
Optical Purity ◽  
Lower Amount ◽  
High Optical Purity ◽  
Initial Substrate ◽  
Initial Ph ◽  
H 30 ◽  
Initial Substrate Concentration

S)-tert-butyl 3-hydroxybutyrate was synthesized by asymmetric reduction of tert-butyl acetoacetate with Saccharomyces cerevisiae B5 as catalyst. The enantiometric excess of (S)-tert-butyl 3-hydroxybutyrate increased with addition of more amount of substrate. High optical purity of product can be obtained when 6 g/L chloroform was used as inhibitor. The optimum reduction time, temperature, and initial pH of reaction mixture were 60 h, 30 °C, and 6.2. Addition of more biomass and lower amount of substrate helped to get high conversion. Conversion and enantiometric excess of product reached 100% when initial substrate concentration and biomass were 2.0 g/L and 140 g/L with 6 g/L chloroform as inhibitor.

Sign in / Sign up

Export Citation Format

Share Document