Dependence of the frequency factor on temperature: The relationship between the reaction extent at the maximum reaction rate and the reaction mechanism

2008 ◽  
Vol 10 (2) ◽  
pp. 226-231 ◽  
Author(s):  
Junmeng Cai ◽  
Ronghou Liu ◽  
Fei Shen
Keyword(s):  
Reaction Mechanism ◽  
Reaction Rate ◽  
Frequency Factor ◽  
Maximum Reaction Rate ◽  
Maximum Reaction ◽  
Reaction Extent ◽  
The Relationship

scholarly journals Synthesis of DHA/EPA Ethyl Esters via Lipase-Catalyzed Acidolysis Using Novozym® 435: A Kinetic Study

Catalysts ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 565 ◽  
Author(s):  
Chia-Hung Kuo ◽  
Chun-Yung Huang ◽  
Chien-Liang Lee ◽  
Wen-Cheng Kuo ◽  
Shu-Ling Hsieh ◽  
...  
Keyword(s):  
Ethyl Ester ◽  
Ethyl Esters ◽  
Raw Material ◽  
Maximum Reaction Rate ◽  
Mechanism Model ◽  
Maximum Reaction ◽  
Substrate Ratio ◽  
Free Fatty Acid Form ◽  
The Relationship ◽  
Predictive Relationship

DHA/EPA ethyl ester is mainly used in the treatment of arteriosclerosis and hyperlipidemia. In this study, DHA+EPA ethyl ester was synthesized via lipase-catalyzed acidolysis of ethyl acetate (EA) with DHA+EPA concentrate in n-hexane using Novozym® 435. The DHA+EPA concentrate (in free fatty acid form), contained 54.4% DHA and 16.8% EPA, was used as raw material. A central composite design combined with response surface methodology (RSM) was used to evaluate the relationship between substrate concentrations and initial rate of DHA+EPA ethyl ester production. The results indicated that the reaction followed the ordered mechanism and as such, the ordered mechanism model was used to estimate the maximum reaction rate (Vmax) and kinetic constants. The ordered mechanism model was also combined with the batch reaction equation to simulate and predict the conversion of DHA+EPA ethyl ester in lipase-catalyzed acidolysis. The integral equation showed a good predictive relationship between the simulated and experimental results. 88–94% conversion yields were obtained from 100–400 mM DHA+EPA concentrate at a constant enzyme activity of 200 U, substrate ratio of 1:1 (DHA+EPA: EA), and reaction time of 300 min.

Biodegradation of 2,4-dichlorophenol in a fluidized bed reactor with immobilized Phanerochaete chrysosporium

2010 ◽  
Vol 62 (4) ◽  
pp. 947-955 ◽  
Author(s):  
Xiao-ming Li ◽  
Qi Yang ◽  
Ying Zhang ◽  
Wei Zheng ◽  
Xiu Yue ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Phanerochaete Chrysosporium ◽  
Reaction Rate ◽  
Immobilized Cells ◽  
Fluidized Bed Reactor ◽  
Degradation Process ◽  
Maximum Reaction Rate ◽  
Monod Equation ◽  
Continuous Bioreactor ◽  
Maximum Reaction

The performance of a fluidized bed reactor using immobilized Phanerochaete chrysosporium to remove 2,4-dichlorophenol (2,4-DCP) from aqueous solution was investigated. The contribution of lignin peroxidase (LiP) and manganese peroxidase (MnP) secreted by Phanerochaete chrysosporium to the 2,4-DCP degradation was examined. Results showed that Lip and Mnp were not essential to 2,4-DCP degradation while their presence enhanced the degradation process and reaction rate. In sequential batch experiment, the bioactivity of immobilized cells was recovered and improved during the culture and the maximum degradation rate constant of 13.95 mg (Ld)−1 could be reached. In continuous bioreactor test, the kinetic behavior of the Phanerochaete chrysosporium immobilized on loofa sponge was found to follow the Monod equation. The maximum reaction rate was 7.002 mg (Lh)−1, and the saturation constant was 26.045 mg L−1.

Basic Studies on Anaerobic Degradation of Glucose in Continuous Stirred Tank Reactors

1991 ◽  
Vol 24 (5) ◽  
pp. 141-147
Author(s):  
Michimasa Nakamura ◽  
Atsushi Sakai ◽  
Jun'ichiro Matsumoto
Keyword(s):  
Anaerobic Degradation ◽  
Volatile Fatty Acid ◽  
Reaction Rate ◽  
Ph Value ◽  
Reaction Rate Constant ◽  
The Other ◽  
Total Volatile ◽  
Maximum Reaction Rate ◽  
Maximum Reaction ◽  
Total Volatile Fatty Acid

The two series of the characteristics of anaerobic degradation of low glucose concentrations were investigated. In the first series, the pH value in each reactor was not controlled. In the second series, the pH value in each reactor was controlled in the range of 6.9–7.2, by adding sodium bicarbonate into each influent. The ORP value was depressed by controlling the pH value of each reactor from acid range to approximately neutral range. In the pH uncontrolled series, the pH value in outflow decreased with increasing glucose concentration. In the pH uncontrolled series, produced total volatile fatty acid was about 70 to 550 mg/l; on the other hand, in pH controlled series, produced total volatile fatty acid was about 50 mg/l to 350 mg/l. The highest concentrations of acids formed were acetic acids, the second highest formed were propionic acids, the last formed were butyric acids. In the pH uncontrolled series, the maximum reaction rate constant Vm was 0.749 gCOD/gVS · day and the saturation constant Ks = 0.435 g/l. On the other hand, in the pH controlled series, the maximum reaction rate constant Vm was 1.441 gCOD/gVS · day and the saturation constant Ks = 0.739 g/l. Thus by controlling the pH value of the reactor, the activities of the anaerobic bacteria were much enhanced.

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