A method for managing a batch fermentation process in a biofuel production process, comprising: providing a nonlinear control model of yeast growth and fermentable sugar concentration for biofuel production in a batch fermentation process of a biofuel production process, wherein yeast grow is based on a theoretical maximal yeast grow rate as a function of temperature, a fermentable sugar concentration, a biofuel concentration, a fermentable sugar saturation constant, a biofuel saturation constant, and a yeast death rate as a function of temperature, and is based on the following equation: yeast growth function = μ x max T y sugar k x 1 + y biofuel k x 2 + y sugar − r d T where: μ x max = theoretical maximum growth rate = f, as a function of T, y sugar = fermentable sugar concentration, y biofuel = biofuels concentration, k x1 = biofuel saturation constant, k x2 = fermentable sugar maturation constant, and r d = yeast death rate = f; receiving process information for the batch fermentation process; executing the nonlinear control model of yeast growth and fermentable sugar concentration using the process information as input to determine values of one or more fermentation process variables for the batch fermentation process for substantially maximizing yeast growth and achieving target fermentable sugar concentrations; and controlling the batch fermentation process in accordance with the determined values for the one or more fermentation process variables to substantially maximize yeast growth and achieve target fermentable sugar concentrations, wherein said substantially maximizing yeast growth and achieving target fermentable sugar concentrations substantially maximizes biofuel production in the batch fermentation process. providing a nonlinear control model of yeast growth and fermentable sugar concentration for biofuel production in a batch fermentation process of a biofuel production process, wherein yeast grow is based on a theoretical maximal yeast grow rate as a function of temperature, a fermentable sugar concentration, a biofuel concentration, a fermentable sugar saturation constant, a biofuel saturation constant, and a yeast death rate as a function of temperature, and is based on the following equation: yeast growth function = μ x max T y sugar k x 1 + y biofuel k x 2 + y sugar − r d T where: μ x max = theoretical maximum growth rate = f, as a function of T, y sugar = fermentable sugar concentration, y biofuel = biofuels concentration, k x1 = biofuel saturation constant, k x2 = fermentable sugar maturation constant, and r d = yeast death rate = f; μ x max = theoretical maximum growth rate = f, as a function of T, y sugar = fermentable sugar concentration, y biofuel = biofuels concentration, k x1 = biofuel saturation constant, k x2 = fermentable sugar maturation constant, and r d = yeast death rate = f; receiving process information for the batch fermentation process; executing the nonlinear control model of yeast growth and fermentable sugar concentration using the process information as input to determine values of one or more fermentation process variables for the batch fermentation process for substantially maximizing yeast growth and achieving target fermentable sugar concentrations; and controlling the batch fermentation process in accordance with the determined values for the one or more fermentation process variables to substantially maximize yeast growth and achieve target fermentable sugar concentrations, wherein said substantially maximizing yeast growth and achieving target fermentable sugar concentrations substantially maximizes biofuel production in the batch fermentation process.