Marie-Laure Lameloise

Recycling of distillery effluents in alcoholic fermentation: role in inhibition of 10 organic molecules.

abstractIn beet distilleries, condensates arising from stillage concentration could be recycled as dilution water for the fermentation step, thus preserving groundwater resources and ensuring a quality-controlled water supply. However, the recycling of condensates has been found to cause a significant reduction in fermentation activity. This study aimed to verify that condensates are toxic to alcoholic fermentation. Ten compounds found in condensates (formic, acetic, propionic, butyric, valeric, and hexanoic acids; 2,3-butanediol, furfuryl alcohol, furfural, and 2-phenyl-ethyl-alcohol) were tested. With the exception of 2,3-butanediol, they all proved to be inhibitors. At the same molar concentration,the longer the carbonaceous chain, the stronger the inhibition by fatty acids. An experimental design was used to study the inhibitory characteristics of the 10 compounds at the concentrations found in condensates. Synergistic effects were also confirmed. In real effluents, acetic acid was so highly concentrated that it became the strongest inhibitor. It is therefore necessary to eliminate it before recycling, as well as less concentrated compounds that may accumulate, as illustrated by the simulation.

Modelling glucose-fructose separation by adsorption chromatography on ion exchange resins

Abstract The objective of this work is the development of a methodology for modelling chromatographic processes involved in the food industry. The methodology is illustrated with glucose-fructose separation which is important in the sugar industry. Equilibrium isotherms are reported for gel ion exchange resins in Ca 2+ form. Independent kinetic and hydrodynamic studies lead to parameters to be used in the complete column chromatographic model. Good agreement between experimental and calculated results is observed at the bench scale which shows the predictive quality of the applied methodology.

Complete Decalcification of Saline Effluent by Associating a Carboxylic Resin with a Chelating Resin

Saline effluent from the glucose industry can be reused as resin regenerants after treatment by a bipolar membrane electrodialysis process preceded by chromatographic decalcification. Ca2+/Na+ isotherms measured on two weak acidic resins showed that the chelating resin has a higher selectivity for calcium. The decalcification process was optimized by combining rough decalcification on a carboxylic resin, followed by a finishing step on a chelating one. This chromatographic system led to the expensive chelating resin being spared and to the treatment of 60% more volume of effluent than with the carboxylic resin alone.