Optimizing alcohol production from whey using computer technology

Abstract

This study was undertaken with the major goal of optimizing the ethanol production from whey using computer technology. To reach this goal, a mathematical model that would describe the fermentation and that could be used for the optimization was developed. Kluyveromyces fragilis was the microorganism used to ferment the lactose in the whey into ethanol. Preliminary studies showed that K. fragilis produced about 90% of the theoretical ethanol yield when grown in whey-complemented media. However, when this yeast is grown in nonsupplemented whey media, it does not produce more than 32% of that yield. Comparative batch fermentations of lactose and whey-complemented media showed that whey possibly contains enhancing components for yeast growth and ethanol production. To obtain the mathematical model, the one-to-one effect of the process variables (lactose and yeast extract concentrations, air flowrate, pH, and dilution rate) on the ethanol production were first investigated. Experiments on the pH effect showed that a decrease in pH from 7 to 4 produced an increase in ethanol concentration from 16.5 to 26.5 g/L (50 g/L initial lactose). The results obtained from modeling of the continuous fermentation using the previously listed variables showed that air flowrate, pH, and dilution rate were the process variables that most influence the production of ethanol.

Fermentation of sweet whey by recombinant Escherichia coli K011

“…The maximum ethanol production (8.3g ethanol/L) was observed at 96h, representing 38% of the theoretical yield. It has been reported that the lactose concentration of whey is around 5% and protein around 0.9% (7,9,18). The limiting factor for whey fermentation by E. coli is essentially the nitrogen, because protein is not an available nitrogen source for this organism.…”

“…Several organisms have been tested for whey fermentation, however, the ethanol production, in general, is low (5,12,17,16). Attempts to improve the ethanol yield from lactose fermentation have been made (1,10,18). The development of the recombinant DNA technology made possible the construction of new strains capable of expressing genes originated from other organisms.…”

Optimization of medium constituents and fermentation conditions for the production of ethanol from palmyra jaggery using response surface methodology

“…Among them, response surface methodology (RSM) is the one suitable method for identifying the effect of individual variables and for seeking the optimum conditions for a multivariable system efficiently. This method has been successfully applied to optimize alcoholic fermentation and other fermentation media (Maddox & Reichert 1977;Chen 1981Chen , 1996Zertuche & Zall 1985;Coteron et al 1993;Sunitha et al 1998;Ambati & Ayyanna 2001;Ratnam 2001;Ratnam et al 2003). A detailed account of this technique has been outlined (Cochran & Cox 1968).…”

A Survey of Modern Optimal Control Methods for Biotechnological Processes

“…-due to the significant duration of the process, there are no reliaЬle criteria for the detection of the equilibrium state-a precondition for starting the identification procedure of the static model (36); -the structure of the dynamic models, which reflects to а certain extent the physical nature of Biotechnology &. BioE 5/1991/6 the process is considered somewhat more informative than the Ьlack-box structure of the regression models.…”

“…An alternative to it is the adoptation of а regression model for the static phase, its parameters being evaluated in а designed experiment (36).…”