title: Nicotinic acid controls lactate production by K1-LDH: a Saccharomyces cerevisiae strain expressing a bacterial LDH gene.
abstract: Industrial applications for lactate, such as the production of chemicals, has led to interest in producing this organic acid by metabolically engineered a yeast such as Saccharomyces cerevisiae, which is more acid tolerant than lactic acid bacteria. This paper deals with lactate production by S. cerevisiae K1-LDH, in which the Lactobacillus plantarum lactate dehydrogenase (LDH) gene is integrated into the genome of the wine yeast strain K1. We show that a vitamin, nicotinic acid (NiA), was the limiting factor for lactate production during fermentation with the K1-LDH strain. Increasing the NiA concentration in batch conditions or in the medium used to feed chemostats affected the lactate yield. Moreover, the addition of pulses of NiA or the exponential addition of NiA made it possible to control the lactate production kinetics throughout the fermentation process. The results point to the role of NiA in the regulation of metabolic pathways, but the physiological mechanisms remain poorly understood.
authors.affiliation: UMR 'Sciences pour l'Oenologie', INRA, 2 place Viala, 34060 Montpellier, France. colombie@ensam.inra.fr
authors.forename: Sophie
authors.initials: S
authors.lastname: Colombié
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Sablayrolles
mesh_terms: D003470:Culture Media; D005285:Fermentation; D007770:L-Lactate Dehydrogenase / Q000235:genetics* / Q000378:metabolism; D019344:Lactic Acid / Q000096:biosynthesis*; D007778:Lactobacillus / Q000235:genetics; D009525:Niacin / Q000378:metabolism / Q000494:pharmacology*; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D014815:Vitamins / Q000378:metabolism / Q000494:pharmacology
chemical_list: D003470:Culture Media; D014815:Vitamins; D009525:Niacin; D019344:Lactic Acid; D007770:L-Lactate Dehydrogenase