IQUIBICEN   23947
INSTITUTO DE QUIMICA BIOLOGICA DE LA FACULTAD DE CIENCIAS EXACTAS Y NATURALES
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
FERMENTATION IN CHEESE WHEY MEDIUM IN A BIOREACTOR TO PRODUCE LACTIC ACID BY GLOBAL REGULATOR ccpA MUTANT OF LACTOBACILLUS CASEI
Autor/es:
CATONE MARIELA V.; M. BLASCO; D.M. LEGISA; RUZAL SANDRA M.; PALOMINO MARIA MERCEDES; ALLIEVI, MARIANA CLAUDIA
Lugar:
San Miguel de Tucuman
Reunión:
Simposio; V Simposio Internacional de Bacterias Lácticas (SIBAL); 2016
Institución organizadora:
CERELA
Resumen:
The lactic acid bacteria (LAB), such as Lactobacillus casei, are microorganisms whose metabolism is strictly fermentative and having high nutritional requirements. The carbohydrate metabolism of LAB is characterized by production of high quantities of lactate as a main product of fermentation. Lactic acid was widely used in food, cosmetic, pharmaceutical, textile, and chemical industries, and much work has been done to improve the production of lactate in a cheap and energy-saving process. To achieve this goal, different strategies have been used as chemical, physical, biochemical and genetic improvements that enable higher performance. The use of waste products from other industrial processes as a source of carbon and energy is a strategy used to reduce costs. The efficient use of nutrients is associated with carbon catabolite repression (CCR), which allows microbes to select their preferred source from multiple offerings of carbon catabolism. The catabolite control protein A (CcpA) is a mediator of CCR in Gram-positive bacteria and also participates in the induction of genes of basic metabolism, including nitrogen metabolism genes, so is considered a global regulator. With the intention to produce lactic acid from industrial waste as a source of carbohydrate, the capacity of lactate production was assessed from a cheese whey based medium. In an attempts to improve the production of lactate from Generally Recognized As Safe microorganisms, we used a fermentation process in a Biostat b Plus bioreactor. We evaluate the fermentation process in Lactobacillus casei BL23 strain (wild type) and ccpA mutant BL71 strain. In both strains, fermentation was performed in batch MRS broth to determine the kinetic parameters by measuring OD 600nm, dry weight (DW) and CFU/ml. For all parameters measured, values of μmax for BL71 were higher than for BL23 strain (μmax DW 0,24 for BL23 and 0,42 for BL71), showing higher growth rate. To assess whether this capability could allow further production of lactic acid from inexpensive substrates, batch fermentations were performed in a medium formulated from cheese whey. Comparing the profiles of base consumption, as an indicator of the ability to produce acidic compounds by strains used, shows a NH4OH consumption at 48 hours of 107 ml for BL71 compared to 2 ml for BL23.This parameter coincides with the higher value on CFU/ml (4,36 x 109 for BL71 and 8,9 x 108 for BL23). We evaluate the lactic acid production in both strains and the possibility of using fed-batch fermentation system. ccpA mutant of Lactobacillus casei is an excellent candidate for future technological developments, enabling the production of lactic acid using carbon sources from industrial wastes such as cheese whey.