45H-10 |
Supplementation of glucose solutions with corn steep liquor for the L-lactic acid production by Lactobacillus delbrueckii |
S. J. Téllez-Luis1, A. B. Moldes2, J. L. Alonso2, and M. VÁZQUEZ3. (1) Dept. of Food Science & Technology, Univ. Autónoma de Tamaulipas, UAM Reynosa-Aztlán, Calle 16 y Lago de Chapala. Col 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 Lactic acid bacteria are generally recognized as nutritionally fastidious. The usual composition of the culture media for lactic acid production by lactobacillus delbrueckii is very complex. A complete medium contains 9 compounds: 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; MgSO4ˇ7H2O, 0.58 g/L; MnSO4ˇH2O, 0.12 g/L and FeSO4ˇ7H2O, 0.05 g/L. The biotechnological production of lactic acid on glucose solutions could be improved using a medium containing corn steep liquor as a sole nutrient, which is a cheap and easily available nutritional compound. This work deals with the evaluation of corn steep liquor to supplement glucose solutions for the production of lactic acid by lactobacillus delbrueckii. Fermentations were conducted in 250 mL flasks with 100 mL final volume at 41.5şC and 150 rpm. The composition of culture media was 90 g glucose/L, 90 g calcium carbonate/L and corn steep liquor at several concentrations (1, 3, 5, 10 or 20 g/L). Calcium carbonate was added to neutralize lactic acid and hold a constant pH. For comparative purpose, fermentation were carried out in the same conditions using the above complete medium. Samples were taken at 0, 6, 23.5, 32 and 53.5 h. Glucose and lactic acid were determined by HPLC with RI detector. Using complete medium up to 63.5 lactic acid g/L was obtained. The lactic acid productivity was 1.19 g/Lh. Using 20 g corn steep liquor/L up to 65.2 lactic acid g/L was achieved with a productivity of 1.22 g/Lh. Lower concentrations of corn steep liquor gave lower production of lactic acid. The results showed that it feasible to use corn steep liquor as sole nutrient in the lactic acid production on glucose solutions.
Session 45H, International: General
|