Modification of the Luedeking and Piret model with a delay time parameter for biotechnological lactic acid production.

Objectives: To obtain a mathematical model that adequately describes the time lag between biomass generation and lactic acid production of lactic fermentations.

Methods: Seven experimental kinetics from other research works were studied to validate our proposal: four studies of Fungal Submerged Fermentation and three cases of Bacterial Submerged Fermentation, including the data recollected by Luedeking and Piret.

Results: We introduce a modification to the Luedeking and Piret model that consist in the introduction of a time delay parameter in the model, this parameter would account for the lag time that exists between the production of biomass and lactic acid.

Kinetics and mathematical model of killer/sensitive interaction under different physicochemical conditions of must/wine: a study from a biological point of view.

Fermentation of grape must to wine is carried out by a complex microbial mixture, which also involves spoilage yeasts of wine. The latter yeasts produce organoleptic changes that cause significant economic losses to the wine industry. SO is traditionally used to control this spoilage populations, but because of its harmful effects on human health, biocontrol has emerged as an alternative treatment.

Modifying the National Research Council weight gain model to estimate daily gain for stockers grazing bermudagrass in the southern United States.

The energy requirements, feed intake, and performance of grazing animals vary daily due to changes in weather conditions, forage nutritive values, and plant and animal maturity throughout the grazing season. Hence, realistic simulations of daily animal performance can be made only by the models that can address these changes. Given the dearth of simple, user-friendly models of this kind, especially for pastures, we developed a daily gain model for large-frame stockers grazing bermudagrass sCynodon dactylon (L.

Effects of biochar and N-stabilizers on greenhouse gas emissions from a subtropical pasture field applied with organic and inorganic nitrogen fertilizers.

Pasturelands contribute significantly to the global CO, CH and NO emissions. These gas emissions are influenced by the amount and type of N-fertilizers applied and local climate. Recent studies showed potential of biochar and N-stabilizer compounds in minimizing CO, CH and NO emissions by regulating N-release from N-fertilizers.

State estimation and nonlinear tracking control simulation approach. Application to a bioethanol production system.

Tracking control of specific variables is key to achieve a proper fermentation. This paper analyzes a fed-batch bioethanol production process. For this system, a controller design based on linear algebra is proposed.