scholarly journals Optimum Design of N Continuous Stirred-Tank Bioreactors in Series for Fermentation Processes Based on Simultaneous Substrate and Product Inhibition

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1419
Author(s):  
Ibrahim M. Abu Reesh
Keyword(s):  
Optimum Design ◽  
Substrate Concentration ◽  
Continuous Fermentation ◽  
Product Inhibition ◽  
Nonlinear Constrained Optimization ◽  
Biochemical Processes ◽  
Substrate Conversion ◽  
Medium Level ◽  
In Series ◽  
Continuous Stirred Tank

Optimization of the continuous fermentation process is important for increasing efficiency and decreasing cost, especially for complicated biochemical processes described by substrate and product inhibition. The optimum design (minimum volume) of CSTRs in series assuming substrate and product inhibition was determined in this study. The effect of operating parameters on the optimum design was investigated. The optimum substrate concentration in the feed to the first reactor was determined for N reactors in series. The nonlinear, constrained optimization problem was solved using the MATLAB function “fmincon”. It was found that the optimum design is more beneficial at high substrate conversion and at a medium level of feed substrate concentration. The best number of reactors is two to three for optimum arrangements and two for equal-size arrangements. The presence of biomass in the feed to the first reactor reduces the reactor volume, while the presence of product in the feed slightly increases the required total volume. The percentage reduction in the total volume using the optimum design compared to equal-volume design (R%) was determined as a function of substrate conversion and substrate concentration in the feed to the first reactor. The obtained R% values agree with experimental data available in the literature for ethanol fermentation.

Initial Studies on the Anaerobic Sequencing Batch Reactor

1992 ◽  
Vol 26 (9-11) ◽  
pp. 2429-2432 ◽  
Author(s):  
R. R. Dague ◽  
C. E. Habben ◽  
S. R. Pidaparti
Keyword(s):  
Substrate Concentration ◽  
Sequencing Batch Reactor ◽  
Batch Reactor ◽  
High Substrate ◽  
Anaerobic Sequencing Batch Reactor ◽  
New Process ◽  
Substrate Conversion ◽  
Solids Separation

This research focuses on an evaluation of the performance of a new process being called the “anaerobic sequencing batch reactor” (ASBR). The ASBR operates on an intermittent, fill and draw regimen. This results in alternating high substrate/low substrate (feast/famine) conditions. The high substrate conditions right after feeding results in high rates of substrate conversion to biogas. The low substrate concentration near the end of the react sequence results in efficient bioflocculation and solids separation.

Lipase-catalyzed synthesis of oligoesters of 2,5-furandicarboxylic acid with aliphatic diols

2015 ◽  
Vol 87 (1) ◽  
pp. 59-69 ◽  
Author(s):  
Álvaro Cruz-Izquierdo ◽  
Lambertus A.M. van den Broek ◽  
Juan L. Serra ◽  
María J. Llama ◽  
Carmen G. Boeriu
Keyword(s):  
Ethylene Glycol ◽  
Chain Length ◽  
Immobilized Lipase ◽  
Product Inhibition ◽  
High Yield ◽  
Alkyl Chains ◽  
Biobased Polymers ◽  
Substrate Conversion ◽  
Furandicarboxylic Acid ◽  
Cyclic Compounds

Abstract2,5-Furandicarboxylic acid is a platform chemical for the production of biobased polymers and materials. This study reports the synthesis of furan oligoesters via polytransesterification of dimethyl furan-2,5-dicarboxylate and linear α, ω-aliphatic diols with chain length ranging from C2 to C12, using immobilized lipase B from Candida antarctica (Novozym 435) in dry organic solvents. Dimethyl furan-2,5-dicarboxylic acid (A) and 1,4-butanediol (B) were used as model substrates under different conditions producing a mixture of cyclic (CEOs) and linear (LEOs) ester oligomers up to decamers and dodecamers, respectively, with high yield. The size of the oligomers and distribution of the products is controlled by the initial concentration of substrates and temperature. While the shortest CEOs are the main cyclic compounds at 20 mM, the longest CEOs are formed at 175 mM. The chain length of the aliphatic diol co-monomers strongly influences the yield and the type of oligoesters formed. High substrate conversion of 90–95 % was obtained for C4–C12 diols, while in the case of ethylene glycol and 1,3-propanediol the conversion was moderate (i.e., 75 %). The product of the reaction between dimethyl furan-2,5-dicarboxylate and ethylene glycol (C2) and 1,3-propanediol (C3), respectively, consisted only of linear oligoesters. Longer oligoesters were obtained for alkyl chains higher than C4. The chain length and the abundance of oligoesters increases in the order: C2<C12<C10<C3<C8<C4 <C6. No substrate or product inhibition was observed in the production of furan-based oligoesters. The present biobased oligoesters are obtained via a green process and have potential application as macromonomers.

Production of Ethanol as a Renewable Energy by Extractive Fermentation

2014 ◽  
Vol 493 ◽  
pp. 300-305 ◽  
Author(s):  
Tri Widjaja ◽  
Ali Altway ◽  
Ayu Ratna Permanasari ◽  
Setiyo Gunawan
Keyword(s):  
Immobilized Cells ◽  
Continuous Fermentation ◽  
Packed Bed ◽  
Extraction Process ◽  
Amyl Alcohol ◽  
Product Inhibition ◽  
Ethanol Productivity ◽  
Extractive Fermentation ◽  
Packed Bed Bioreactor ◽  
Recycle Ratio

One issue with batch fermentation is that product inhibition causes low yields and ethanol productivity. The objective of this study was to increase the yield and ethanol productivity via continuous fermentation in a packed bed bioreactor with both an integrated extraction process and recycling of the raffinate into the fermenter. Molasses was used as the feedstock, and the immobilized cells were supported by ĸ-carrageenan. This process used n-amyl alcohol, 1-octanol, and 1-dodecanol as solvents. The yield and ethanol productivity increased from 8.79% to 20.03% and 34.54 g/L·h to 118.16 g/L·h for experiments using n-amyl alcohol, 9.05% to 12.67% and 35.59 g/L·h to 74.71 g/L·h, for 1-dodecanol, 8.89% to 13.45% and 34.93 g/L·h to 84.62 g/L·h, for1-octanol by increasing recycle ratio from 0 to 0.5. Based on these results, n-amyl alcohol was the best solvent for the extractive fermentation process.

Tanks in Series Model for Continuous Stirred Tank Electrochemical Reactor

2008 ◽  
Vol 47 (9) ◽  
pp. 2976-2984 ◽  
Author(s):  
R. Saravanathamizhan ◽  
R. Paranthaman ◽  
N. Balasubramanian ◽  
C. Ahmed Basha
Keyword(s):  
Electrochemical Reactor ◽  
Stirred Tank ◽  
In Series ◽  
Continuous Stirred Tank

scholarly journals Design and Simulation of Hierarchical Control of Two Continuous Stirred Tank Heater in Series

2016 ◽  
Vol 9 (21) ◽  
Author(s):  
Normah Abdullah ◽  
Ramin Razmi ◽  
Tan Chung Chuan ◽  
Zulkifli Mohd Nopiah ◽  
Azah Mohamed ◽  
...  
Keyword(s):  
Hierarchical Control ◽  
Stirred Tank ◽  
In Series ◽  
Continuous Stirred Tank

scholarly journals Reexamining Michaelis-Menten enzyme kinetics for xanthine oxidase

2013 ◽  
Vol 37 (1) ◽  
pp. 37-48 ◽  
Author(s):  
James B. Bassingthwaighte ◽  
Tamara M. Chinn
Keyword(s):  
Xanthine Oxidase ◽  
Enzyme Concentration ◽  
Product Inhibition ◽  
Parameter Estimates ◽  
Michaelis Constant ◽  
Binding Model ◽  
Initial Substrate ◽  
In Series ◽  
Substrate Concentrations

Abbreviated expressions for enzyme kinetic expressions, such as the Michaelis-Menten (M-M) equations, are based on the premise that enzyme concentrations are low compared with those of the substrate and product. When one does progress experiments, where the solute is consumed during conversion to form a series of products, the idealized conditions are violated. Here, we analyzed data of xanthine oxidase in vitro from Escribano et al. ( Biochem J 254: 829, 1988) on two conversions in series, hypoxanthine to xanthine to uric acid. Analyses were done using four models: standard irreversible M-M reactions ( model 1), Escribano et al.'s M-M forward reaction expressions with product inhibition ( model 2), fully reversible M-M equations ( model 3), and standard differential equations allowing forward and backward reactions with mass balance accounting for binding ( model 4). The results showed that the need for invoking product inhibition vanishes with more complete analyses. The reactions were not quite irreversible, so the backward reaction had a small effect. Even though the enzyme concentration was only 1–2% of the initial substrate concentrations, accounting for the fraction of solutes bound to the enzyme did influence the parameter estimates, but in this case, the M-M model overestimated Michaelis constant values by only about one-third. This article also presents the research and models in a reproducible and publicly available form.

Model-based study of nitrite accumulation with OUR control in two continuous nitrifying activated sludge configurations

2009 ◽  
Vol 60 (10) ◽  
pp. 2685-2693 ◽  
Author(s):  
Irene Jubany ◽  
Juan Antonio Baeza ◽  
Javier Lafuente ◽  
Julian Carrera
Keyword(s):  
Partial Nitrification ◽  
Nitrite Accumulation ◽  
Good Tool ◽  
Free Nitrous Acid ◽  
Stirred Tank Reactors ◽  
Inhibitory Compounds ◽  
Nitrite Oxidizing Bacteria ◽  
In Series ◽  
Continuous Stirred Tank ◽  
Different Characteristics

Achievement of partial nitrification relies on the different characteristics of the microorganisms involved in the two steps of nitrification (AOB, ammonium oxidizing bacteria and NOB, nitrite oxidizing bacteria). Several configurations and conditions have been used to achieve partial nitrification taking into account their different responses in front of some environmental conditions like pH, temperature (T), dissolved oxygen (DO) and the inhibitory compounds free ammonia (FA) and free nitrous acid (FNA). This work is a theoretical study about the utilization of a control strategy based on controlling OUR by manipulating the influent flow-rate together with additional changes in T, pH or DO for achieving stable partial nitrification. Two different configurations were simulated. Configuration A consisted of three continuous stirred-tank reactors in series plus a settler, while configuration B consisted of a single reactor with the same total volume and a settler. The developed control system was shown as a good tool to achieve partial nitrification with both configurations. Nevertheless, configuration A showed better results and partial nitrification was obtained even under theoretically unfavourable conditions as T = 15°C, pH = 8.3 and DO = 3 mg O2 L−1.

scholarly journals LEVEL OF COMPREHENSION AMONG MALAYSIAN UNIVERSITY STUDENTS ON THE 1 MALAYSIA CONCEPT

2020 ◽  
Vol 2 (5) ◽  
pp. 46-59
Author(s):  
Muhammad Fuad Othman ◽  
Zaheruddin Othman ◽  
Mohamad Ainuddin Iskandar Lee Abdullah ◽  
Fairol Halim ◽  
Abdul Rahman Abdul Aziz ◽  
...  
Keyword(s):  
Higher Education ◽  
University Students ◽  
Quantitative Research ◽  
Early Stage ◽  
School Level ◽  
National Unity ◽  
Medium Level ◽  
In Series ◽  
Level Of Understanding ◽  
Grant Scheme

The process to cultivate a sense of solidarity among Malaysians must start from the early stage moreover university students as they are future leaders. Therefore, this study was conducted to evaluate the understanding of the 1Malaysia concept among students of Higher Education Institutions (IPT). The methods of this study were quantitative research and the research questions are to evaluate the level of understanding of the 1Malaysia concept among (IPT) This study was conducted through the dissemination of questionnaires and the sample consisted of local (IPT) students. A total of 1000 manuscripts were distributed and from that 478 manuscripts were returned and analyzed through the SPSS program in series 22. This research found that most (IPT) students are on a medium level of understanding of the 1Malaysia concept. In addition, this study found that these students lack the will to assimilate among them in totality which is the chief objective of the 1Malaysia concept. Therefore, it is recommended that the cultivation of the spirit of unity must begin from as early as the family unit and also at the pre-school level. In addition, emphasis should also be given to the usage of the Malay language as the official language of unity and learning in the universities. It is also recommended that reforms must be made and that elements of national unity must be embedded in all university programs so that it will inculcate openness and acceptance among all citizens towards true national unity. This research was funded under the Ministry of Higher Education Fundamental Research Grant Scheme (FRGS)

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