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Instantaneous and overall indicators for determination of bottleneck ranking in metabolic reaction networks / Kansuporn Sriyudthsak in Industrial & engineering chemistry research, Vol. 49 N° 5 (Mars 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 5 (Mars 2010) . - pp. 2122–2129 Titre : Instantaneous and overall indicators for determination of bottleneck ranking in metabolic reaction networks Type de document : texte imprimé Auteurs : Kansuporn Sriyudthsak, Auteur ; Fumihide Shiraishi, Auteur Année de publication : 2010 Article en page(s) : pp. 2122–2129 Note générale : Industrial Chemistry Langues : Anglais (eng) Mots-clés : Metabolic  Reaction  Networks Résumé : A dynamic logarithmic gain expresses the percentage change in a dependent variable or metabolite concentration in response to an infinitesimal percentage change in an independent variable or enzyme activity. This article discusses the usefulness of several bottleneck ranking (BR) indicators that are functions of the logarithmic gain, to determine the most likely bottleneck enzyme in a dynamic metabolic reaction system. Mathematical models for penicillin V and ethanol fermentations are considered as case studies. The calculated results reveal that the instantaneous BR indicator, which is a product of the dynamic logarithmic gain and the metabolite concentration, is an effective measure for instantaneous bottleneck enzyme ranking changed during the fermentation period, whereas the overall BR indicator, which is a time-averaged value of the instantaneous BR indicator, is an effective measure for bottleneck enzyme ranking throughout the entire fermentation period. Note de contenu : Bibliogr. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901531d [article] Instantaneous and overall indicators for determination of bottleneck ranking in metabolic reaction networks [texte imprimé] / Kansuporn Sriyudthsak, Auteur ; Fumihide Shiraishi, Auteur . - 2010 . - pp. 2122–2129. Industrial Chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 5 (Mars 2010) . - pp. 2122–2129 Mots-clés : Metabolic  Reaction  Networks Résumé : A dynamic logarithmic gain expresses the percentage change in a dependent variable or metabolite concentration in response to an infinitesimal percentage change in an independent variable or enzyme activity. This article discusses the usefulness of several bottleneck ranking (BR) indicators that are functions of the logarithmic gain, to determine the most likely bottleneck enzyme in a dynamic metabolic reaction system. Mathematical models for penicillin V and ethanol fermentations are considered as case studies. The calculated results reveal that the instantaneous BR indicator, which is a product of the dynamic logarithmic gain and the metabolite concentration, is an effective measure for instantaneous bottleneck enzyme ranking changed during the fermentation period, whereas the overall BR indicator, which is a time-averaged value of the instantaneous BR indicator, is an effective measure for bottleneck enzyme ranking throughout the entire fermentation period. Note de contenu : Bibliogr. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie901531d

Method for determination of the main bottleneck enzyme in a metabolic reaction network by dynamic sensitivity analysis / Fumihide Shiraishi in Industrial & engineering chemistry research, Vol. 48 N°1 (Janvier 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N°1 (Janvier 2009) . - P. 415-423 Titre : Method for determination of the main bottleneck enzyme in a metabolic reaction network by dynamic sensitivity analysis Type de document : texte imprimé Auteurs : Fumihide Shiraishi, Editeur scientifique ; Yusuke Suzuki, Editeur scientifique Année de publication : 2009 Article en page(s) : P. 415-423 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Enzyme  Dynamic  logarithmic  gains Résumé : In fermentation processes, it is important to identify the bottleneck enzyme in a given metabolic reaction network, because increasing its activity would lead to an enhancement in the productivity of a desired metabolite. To efficiently identify the bottleneck enzyme, the present work discusses a systematic approach using dynamic logarithmic gains, i.e., percentage changes in the concentration of the desired metabolite in the response to an infinitesimal percentage change in enzyme activities, as an indicator. A penicillin V fed-batch fermentation model proposed by other researchers was used as an example of application. The calculated results showed that not only the time courses of the dynamic logarithmic gains but also the ranking of the magnitudes of their values is changed with time, implying that the bottleneck enzyme is changed with time in this fermentation process. To determine the bottleneck enzyme from such time-transient behaviors, the dynamic logarithmic gains were integrated over the entire fermentation period and divided by the total process time. The time-averaged dynamic logarithmic gains thus calculated were then ranked according to the magnitudes of their values. However, this ranking, corresponding to the ranking of candidate bottleneck enzymes, was not identical to that obtained with regard to the total amount of the desired metabolite produced as a result of finite change in each enzyme activity. This is because the concentration of the substrate for the reaction catalyzed by the relevant enzyme displays a decreasing behavior, so that the degree of increase in the corresponding flux was smaller for the finite increase of the enzyme activity and the total amount of the desired metabolite did not proportionally increase. When the concentration of the substrate for the reaction catalyzed by the most likely bottleneck enzyme displays a decreasing behavior, therefore, it is necessary to check not only the ranking of the time-average dynamic logarithmic gains but also whether the total amount of the desired metabolite is ranked first when the relevant enzyme activity is finitely changed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8005963 [article] Method for determination of the main bottleneck enzyme in a metabolic reaction network by dynamic sensitivity analysis [texte imprimé] / Fumihide Shiraishi, Editeur scientifique ; Yusuke Suzuki, Editeur scientifique . - 2009 . - P. 415-423. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N°1 (Janvier 2009) . - P. 415-423 Mots-clés : Enzyme  Dynamic  logarithmic  gains Résumé : In fermentation processes, it is important to identify the bottleneck enzyme in a given metabolic reaction network, because increasing its activity would lead to an enhancement in the productivity of a desired metabolite. To efficiently identify the bottleneck enzyme, the present work discusses a systematic approach using dynamic logarithmic gains, i.e., percentage changes in the concentration of the desired metabolite in the response to an infinitesimal percentage change in enzyme activities, as an indicator. A penicillin V fed-batch fermentation model proposed by other researchers was used as an example of application. The calculated results showed that not only the time courses of the dynamic logarithmic gains but also the ranking of the magnitudes of their values is changed with time, implying that the bottleneck enzyme is changed with time in this fermentation process. To determine the bottleneck enzyme from such time-transient behaviors, the dynamic logarithmic gains were integrated over the entire fermentation period and divided by the total process time. The time-averaged dynamic logarithmic gains thus calculated were then ranked according to the magnitudes of their values. However, this ranking, corresponding to the ranking of candidate bottleneck enzymes, was not identical to that obtained with regard to the total amount of the desired metabolite produced as a result of finite change in each enzyme activity. This is because the concentration of the substrate for the reaction catalyzed by the relevant enzyme displays a decreasing behavior, so that the degree of increase in the corresponding flux was smaller for the finite increase of the enzyme activity and the total amount of the desired metabolite did not proportionally increase. When the concentration of the substrate for the reaction catalyzed by the most likely bottleneck enzyme displays a decreasing behavior, therefore, it is necessary to check not only the ranking of the time-average dynamic logarithmic gains but also whether the total amount of the desired metabolite is ranked first when the relevant enzyme activity is finitely changed. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie8005963

Photocatalytic and adsorptive treatment of 2,4-dinitrophenol using a TiO2 film covering activated carbon surface / Xiangyu Cao in Chemical engineering journal, Vol. 156 N° 1 (Janvier 2010) 

Public ISBD [article]  in Chemical engineering journal > Vol. 156 N° 1 (Janvier 2010) . - pp. 98-105 Titre : Photocatalytic and adsorptive treatment of 2,4-dinitrophenol using a TiO2 film covering activated carbon surface Type de document : texte imprimé Auteurs : Xiangyu Cao, Auteur ; Yasuhiro Oda, Auteur ; Fumihide Shiraishi, Auteur Année de publication : 2010 Article en page(s) : pp. 98-105 Note générale : Génie Chimique Langues : Anglais (eng) Mots-clés : Photocatalytic  reaction  Titanium  dioxide  Activated  carbon  Adsorption  Batch-recirculation  reactor Index. décimale : 660 Résumé : Anatase titanium dioxide (TiO2) in particle sizes of roughly 0.5–20 μm was prepared from amorphous TiO2 in an aqueous H2O2 solution by heating at 90 °C for 9 h and directly deposited on a PET film. On the other hand, granular activated carbon (AC) particles in sizes of 1–2 mm in diameter were adhesively deposited on a PET film, and their surfaces were also coated with TiO2. The resulting three preparations (TiO2-, AC-, and TiO2/AC-PET films) were set up in an annular-flow reactor to treat aqueous solutions of 2,4-dinitrophenol (DNP) in a batch-recirculation mode. The rate of DNP adsorption onto the TiO2/AC-PET film without UV irradiation was almost the same as that onto the AC-PET film, indicating that the attraction of DNP to AC was not lowered in the presence of TiO2 film. Observation of SEM photographs suggests that this result is attributed to the porous structure of the thin TiO2 film covering AC particles. The rate of DNP removal by the TiO2-AC PET film under UV irradiation was 2.9 times higher than that by the TiO2-PET film under UV irradiation, and was 1.1 times higher than the rate of DNP adsorption onto the AC-PET film. The rate of DNP removal by the AC-PET film decreased by 40% after six runs, while that by the TiO2/AC-PET film decreased by 22%. Durable experiments using the TiO2/AC-PET and AC-PET films clarified that the lifetime of the TiO2/AC-PET film is at least two times longer than that of the AC-PET film. This result suggests that DNP molecules are photocatalytically decomposed when passing through the porous TiO2-PET film, which lessens a burden of DNP adsorption on AC. Moreover, the DNP treatments in the batch-recirculation flow system suggested that the TiO2/AC-PET film saturated with DNP can be successfully regenerated at 60 °C. DEWEY : 660 ISSN : 1385-8947 En ligne : http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TFJ-4XF840K-4&_user=6 [...] [article] Photocatalytic and adsorptive treatment of 2,4-dinitrophenol using a TiO2 film covering activated carbon surface [texte imprimé] / Xiangyu Cao, Auteur ; Yasuhiro Oda, Auteur ; Fumihide Shiraishi, Auteur . - 2010 . - pp. 98-105. Génie Chimique Langues : Anglais (eng) in Chemical engineering journal > Vol. 156 N° 1 (Janvier 2010) . - pp. 98-105 Mots-clés : Photocatalytic  reaction  Titanium  dioxide  Activated  carbon  Adsorption  Batch-recirculation  reactor Index. décimale : 660 Résumé : Anatase titanium dioxide (TiO2) in particle sizes of roughly 0.5–20 μm was prepared from amorphous TiO2 in an aqueous H2O2 solution by heating at 90 °C for 9 h and directly deposited on a PET film. On the other hand, granular activated carbon (AC) particles in sizes of 1–2 mm in diameter were adhesively deposited on a PET film, and their surfaces were also coated with TiO2. The resulting three preparations (TiO2-, AC-, and TiO2/AC-PET films) were set up in an annular-flow reactor to treat aqueous solutions of 2,4-dinitrophenol (DNP) in a batch-recirculation mode. The rate of DNP adsorption onto the TiO2/AC-PET film without UV irradiation was almost the same as that onto the AC-PET film, indicating that the attraction of DNP to AC was not lowered in the presence of TiO2 film. Observation of SEM photographs suggests that this result is attributed to the porous structure of the thin TiO2 film covering AC particles. The rate of DNP removal by the TiO2-AC PET film under UV irradiation was 2.9 times higher than that by the TiO2-PET film under UV irradiation, and was 1.1 times higher than the rate of DNP adsorption onto the AC-PET film. The rate of DNP removal by the AC-PET film decreased by 40% after six runs, while that by the TiO2/AC-PET film decreased by 22%. Durable experiments using the TiO2/AC-PET and AC-PET films clarified that the lifetime of the TiO2/AC-PET film is at least two times longer than that of the AC-PET film. This result suggests that DNP molecules are photocatalytically decomposed when passing through the porous TiO2-PET film, which lessens a burden of DNP adsorption on AC. Moreover, the DNP treatments in the batch-recirculation flow system suggested that the TiO2/AC-PET film saturated with DNP can be successfully regenerated at 60 °C. DEWEY : 660 ISSN : 1385-8947 En ligne : http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TFJ-4XF840K-4&_user=6 [...]

Selection of best indicators for ranking and determination of bottleneck enzymes in metabolic reaction systems / Kansuporn Sriyudthsak in Industrial & engineering chemistry research, Vol. 49 N° 20 (Octobre 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9738–9742 Titre : Selection of best indicators for ranking and determination of bottleneck enzymes in metabolic reaction systems Type de document : texte imprimé Auteurs : Kansuporn Sriyudthsak, Auteur ; Fumihide Shiraishi, Auteur Année de publication : 2011 Article en page(s) : pp. 9738–9742 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Enzymes  Metabolic  reaction Résumé : Dynamic logarithmic gain and its modifications can be theoretically used as a bottleneck ranking (BR) indicator in a metabolic reaction system. However, it is not sufficiently explicit whether they can be successfully used in practical applications. The present work therefore focuses on the selection of best BR indicators in both instantaneous and overall cases. A modified ethanol fermentation model is used as a case study. The results indicate that the mathematical product of dynamic logarithmic gain and desired product concentration at a given time is the best instantaneous BR indicator, whereas its value at the end time of the fermentation process is the best overall BR indicator. The former is useful for observing the time course of the desired product concentration and determining a process time to be terminated. The latter is for ranking bottleneck enzymes to determine which enzyme activity should be changed to attain a higher desired product concentration. Moreover, discussion is made on the utilization of the overall BR indicators to predict how much the final desired product concentration is increased. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100911h [article] Selection of best indicators for ranking and determination of bottleneck enzymes in metabolic reaction systems [texte imprimé] / Kansuporn Sriyudthsak, Auteur ; Fumihide Shiraishi, Auteur . - 2011 . - pp. 9738–9742. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 20 (Octobre 2010) . - pp. 9738–9742 Mots-clés : Enzymes  Metabolic  reaction Résumé : Dynamic logarithmic gain and its modifications can be theoretically used as a bottleneck ranking (BR) indicator in a metabolic reaction system. However, it is not sufficiently explicit whether they can be successfully used in practical applications. The present work therefore focuses on the selection of best BR indicators in both instantaneous and overall cases. A modified ethanol fermentation model is used as a case study. The results indicate that the mathematical product of dynamic logarithmic gain and desired product concentration at a given time is the best instantaneous BR indicator, whereas its value at the end time of the fermentation process is the best overall BR indicator. The former is useful for observing the time course of the desired product concentration and determining a process time to be terminated. The latter is for ranking bottleneck enzymes to determine which enzyme activity should be changed to attain a higher desired product concentration. Moreover, discussion is made on the utilization of the overall BR indicators to predict how much the final desired product concentration is increased. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100911h