46E-16 |
Evaluation of culture media with corn steep liquor on lactic acid production by lactobacillus delbrueckii |
S. J. Téllez-Luis1, A. B. Moldes2, M. VÁZQUEZ3, and J. L. Alonso2. (1) Department of Food Science and Technology, Universidad Autónoma de Tamaulipas, UAM Reynosa-Aztlán, Reynosa, Tamaulipas, 88740, Mexico, (2) Department of Chemical Engineering, Universidad de Vigo, Facultad de Ciencias, Ourense, 32004, Spain, (3) Department of Analytical Chemistry - Area Food Technology, Universidad de Santiago de Compostela, Escuela Politécnica Superior, Lugo, 27002, Spain The common composition of the culture media for lactic acid production by lactobacillus delbrueckii is very complex. A complete medium contains: yeast extract, 5 g/L; peptone, 10 g/L; sodium acetate, 5 g/L; sodium citrate, 2 g/L; K2HPO4, 2 g/L; tween 80, 1 mL/L; MgSO4·7H2O, 0.58 g/L; MnSO4·H2O, 0.12 g/L and FeSO4·7H2O, 0.05 g/L. The biotechnological production of lactic acid could be improved using a medium containing a mixture of corn steep liquor with only a nutrient of the complete medium. The objective of this study was to determine the effect of mixture of corn steep liquor with components of the complete medium on the production of lactic acid by lactobacillus delbrueckii growing on glucose solutions. Fermentations were conducted in 250 mL flasks with 100 mL final volume at 41.5ºC and 150 rpm. The composition of culture media was 90 g glucose/L, 90 g calcium carbonate/L, corn steep liquor (10 g/L) and only one of the components of the complete medium in the above concentration. Calcium carbonate was added to neutralize lactic acid and hold a constant pH. Fermentation were also carried out in the same conditions using above complete medium. Samples were taken in the range 0 - 53.5 h. Glucose and lactic acid were determined by HPLC with RI detector. Using a complete medium up to 63.5 lactic acid g/L was obtained. Using corn steep liquor (10 g/L) with yeast extract (5 g/L) up to 87.2 lactic acid g/L was achieved with a productivity of 1.54 g/Lh. Fermentations containing corn steep liquor with one of the other components gave lower concentration of lactic acid. The results showed that higher lactic acid concentrations can be obtained using corn steep liquor with yeast extract than using a complete medium.
Session 46E, International
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