Method for Regulating Oscillatory Dynamic Behavior in a Zymomonas mobiliz Continuous Fermentation Process

Mathematical modeling and parameter estimation are critical steps in the optimization of biotechnological processes. In the 1,3-propanediol (1,3-PD) production by glycerol fermentation process under anaerobic conditions, 3-hydroxypropionaldehyde (3-HPA) accumulation would arouse an irreversible cessation of the fermentation process. Considering 3-HPA inhibitions to cells growth and to activities of enzymes, we propose a novel mathematical model to describe glycerol continuous cultures. Some properties of the above model are discussed. On the basis of the concentrations of extracellular substances, a parameter identification model is established to determine the kinetic parameters in the presented system. Through the penalty function technique combined with an extension of the state space method, an improved genetic algorithm is then constructed to solve the parameter identification model. An illustrative numerical example shows the appropriateness of the proposed model and the validity of optimization algorithm. Since it is difficult to measure the concentrations of intracellular substances, a quantitative robustness analysis method is given to infer whether the model is plausible for the intracellular substances. Numerical results show that the proposed model is of good robustness.

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Modelling and adaptive predictive control of a continuous fermentation process

Applied Mathematical Modelling ◽

10.1016/0307-904x(92)90004-m ◽

1992 ◽

Vol 16 (10) ◽

pp. 545-552 ◽

Cited By ~ 9

Author(s):

B. Dahhou ◽

G. Roux ◽

G. Chamilothoris

Keyword(s):

Predictive Control ◽

Fermentation Process ◽

Continuous Fermentation ◽

Adaptive Predictive Control

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Characterization and Dynamic Behavior of Wild Yeast during Spontaneous Wine Fermentation in Steel Tanks and Amphorae

BioMed Research International ◽

10.1155/2013/540465 ◽

2013 ◽

Vol 2013 ◽

pp. 1-13 ◽

Cited By ~ 41

Author(s):

Cecilia Díaz ◽

Ana María Molina ◽

Jörg Nähring ◽

Rainer Fischer

Keyword(s):

Dynamic Behavior ◽

Fermentation Process ◽

Pilot Scale ◽

Wine Fermentation ◽

Lag Phase ◽

Wild Yeast ◽

Spoilage Yeasts ◽

Wild Yeasts ◽

Red Grape ◽

Grape Varieties

We studied the dynamic behavior of wild yeasts during spontaneous wine fermentation at a winery in the Valais region of Switzerland. Wild yeasts in the winery environment were characterized using a PCR-RFLP method. Up to 11 different yeast species were isolated from the vineyard air, whereas only seven were recovered from the grapes surface. We initially investigated a cultureindependent method in pilot-scale steel fermentation tanks and found a greater diversity of yeasts in the musts from two red grape varieties compared to three white grape varieties. We found that the yeastsMetschnikowia pulcherrima,Rhodotorula mucilaginosa,Pichia kluyveri,P. membranifaciensandSaccharomyces cerevisiaeremained active at the end of the fermentation. We also studied the dynamic behavior of yeasts in Qvevris for the first time using a novel, highlysensitive quantitative real-time PCR method. We found that non-Saccharomycesyeasts were present during the entire fermentation process, withR. mucilaginosaandP. anomalathe most prominent species. We studied the relationship between the predominance of different species and the output of the fermentation process. We identified so-called spoilage yeasts in all the fermentations, but high levels of acetic acid accumulated only in those fermentations with an extended lag phase.

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