TY - JOUR
T1 - Dynamics and modeling on fermentative production of poly (β-hydroxybutyric acid) from sugars via lactate by a mixed culture of Lactobacillus delbrueckii and Alcaligenes eutrophus
AU - Katoh, Tomoji
AU - Yuguchi, Daisuke
AU - Yoshii, Haruki
AU - Shi, Huidong
AU - Shimizu, Kazuyuki
N1 - Funding Information:
This work was supported in part by a Grant-in-Aid for Scientific Research (No. 10650789) from the Ministry of Education and Science, Japan.
PY - 1999/1/22
Y1 - 1999/1/22
N2 - The mixed culture system was considered in the present research where sugars such as glucose were converted to lactate by Lactobacillus delbrueckii and the lactate was converted to poly β-hydroxybutyrate (PHB) by Alcaligenes eutrophus in one fermentor. For the modeling of the effect of NH3 concentration on the cell growth of A. eutrophus and PHB production rates, metabolic flux distributions were computed at two culture phases of cell growth and PHB production periods. It was found that the NADPH, generated through isocitrate dehydrogenate in TCA cycle, was predominantly utilized for the reaction from α-ketoglutalate to glutamate when NH3 was abundant, while it tended to be utilized for the PHB production through acetoacetyl CoA reductase as NH3 concentration decreased. This phenomenon was reflected in the development of mathematical model. In the mixed culture experiments, the two phases were observed, namely the lactate production phase due to L. delbrueckii and the lactate consumption phase due to A. eutrophus. The lactate concentration could be estimated on-line by the amount of NaOH solution and HCl solution supplied to keep the culture pH at constant level. Several mixed culture experiments were conducted to see the dynamics of the system. Finally, a mathematical model which can describe the dynamic behavior of the present mixed culture was developed and the model parameters were tuned for fitting the experimental data. The model may be used for several purposes such as control, optimization, and understanding process dynamics etc. Copyright (C) 1999 Elsevier Science B.V.
AB - The mixed culture system was considered in the present research where sugars such as glucose were converted to lactate by Lactobacillus delbrueckii and the lactate was converted to poly β-hydroxybutyrate (PHB) by Alcaligenes eutrophus in one fermentor. For the modeling of the effect of NH3 concentration on the cell growth of A. eutrophus and PHB production rates, metabolic flux distributions were computed at two culture phases of cell growth and PHB production periods. It was found that the NADPH, generated through isocitrate dehydrogenate in TCA cycle, was predominantly utilized for the reaction from α-ketoglutalate to glutamate when NH3 was abundant, while it tended to be utilized for the PHB production through acetoacetyl CoA reductase as NH3 concentration decreased. This phenomenon was reflected in the development of mathematical model. In the mixed culture experiments, the two phases were observed, namely the lactate production phase due to L. delbrueckii and the lactate consumption phase due to A. eutrophus. The lactate concentration could be estimated on-line by the amount of NaOH solution and HCl solution supplied to keep the culture pH at constant level. Several mixed culture experiments were conducted to see the dynamics of the system. Finally, a mathematical model which can describe the dynamic behavior of the present mixed culture was developed and the model parameters were tuned for fitting the experimental data. The model may be used for several purposes such as control, optimization, and understanding process dynamics etc. Copyright (C) 1999 Elsevier Science B.V.
KW - Dynamics
KW - Metabolic pathway analysis
KW - Mixed culture
KW - Modeling
KW - PHB fermentation
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U2 - 10.1016/S0168-1656(98)00177-1
DO - 10.1016/S0168-1656(98)00177-1
M3 - Article
C2 - 9990731
AN - SCOPUS:0032944307
SN - 0168-1656
VL - 67
SP - 113
EP - 134
JO - Journal of Biotechnology
JF - Journal of Biotechnology
IS - 2-3
ER -