Vitae (Feb 2009)
EVALUATION OF AN EXTRACTIVE FERMENTATION SYSTEM FOR THE PRODUCTION OF LACTIC ACID USING WHEY AS SUBSTRATE
Abstract
In this work the technique of in situ extractive fermentation is applied for the production and separation of lactic acid, using whey as substrate and Lactobacillus delbrueckii spp. bulgaricus. The technique consists on the use of an organic phase in contact with a culture medium that allows the direct extraction of a compound as it is produced during the fermentation. The organic phase used is composed by a non polar solvent (hexane, heptane and iso-octane) and tributyl phosphate, TBP as extracting agent. Toxicity of the organic phase onto the microorganism and its extracting capacity of lactic acid are tested, and finding that the best results were obtained with hexane-TBP. Later on, the extractive fermentation was carried out with a central composite design using pH, % (v/v) of TBP in the organic phase and % (v/v) the water phase as factors. The response variable analyzed were the concentration of lactic acid in the culture medium (ALFA) and the partition coefficient Kd, displaying the mathematical models that describe their behavior. It finding that pH is the more significant factor during the process.
