title: Effect of ethanol and low pH on citrulline and ornithine excretion and arc gene expression by strains of Lactobacillus brevis and Pediococcus pentosaceus.
abstract: The accumulation of citrulline and ornithine in wine or beer as a result of the arginine catabolism of some lactic acid bacteria (LAB) species increases the risk of ethyl carbamate and putrescine formation, respectively. Several LAB species, which are found as spoilage bacteria in alcoholic beverages, have been reported to be arginine degrading. This study evaluates the effect of ethanol content and low pH on the excretion of citrulline and ornithine by two strains belonging to the potential contaminant species Lactobacillus brevis and Pediococcus pentosaceus. In the conditions that most affected cell viability, arginine consumption per cell increased noticeably, indicating that arginine utilization may be a stress responsive mechanism. L. brevis showed a higher accumulation of ornithine in the media than P. pentosaceus. In the presence of ethanol, a higher expression of the arcC gene was found in P. pentosaceus, which resulted in a lower excretion of citrulline and ornithine than in L. brevis. This suggests that L. brevis is more likely to produce these amino acids, which are precursors of ethyl carbamate and putrescine.
authors.affiliation: Departament de Bioquímica i Biotecnologia, Universitat Rovira i Virgili, Campus Sescelades N4, C. Marcel.lí Domingo 1, Tarragona 43007, Catalonia, Spain.
authors.forename: Isabel
authors.initials: I
authors.lastname: Araque
authors.forename: Albert
authors.initials: A
authors.lastname: Bordons
authors.forename: Cristina
authors.initials: C
authors.lastname: Reguant
mesh_terms: D001120:Arginine / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D002956:Citrulline / Q000378:metabolism*; D000431:Ethanol / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D006863:Hydrogen-Ion Concentration; D052196:Levilactobacillus brevis / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D009952:Ornithine / Q000378:metabolism*; D010376:Pediococcus / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D017851:Phosphotransferases (Carboxyl Group Acceptor) / Q000235:genetics* / Q000378:metabolism; D014920:Wine / Q000032:analysis / Q000382:microbiology
chemical_list: D001426:Bacterial Proteins; D002956:Citrulline; D000431:Ethanol; D001120:Arginine; D009952:Ornithine; D017851:Phosphotransferases (Carboxyl Group Acceptor); C019288:carbamate kinase