@article{mbs:/content/journal/micro/10.1099/mic.0.024737-0, author = "Arioli, Stefania and Roncada, Paola and Salzano, Anna Maria and Deriu, Francesca and Corona, Silvia and Guglielmetti, Simone and Bonizzi, Luigi and Scaloni, Andrea and Mora, Diego", title = "The relevance of carbon dioxide metabolism in Streptococcus thermophilus", journal= "Microbiology", year = "2009", volume = "155", number = "6", pages = "1953-1965", doi = "https://doi.org/10.1099/mic.0.024737-0", url = "https://www.microbiologyresearch.org/content/journal/micro/10.1099/mic.0.024737-0", publisher = "Microbiology Society", issn = "1465-2080", type = "Journal Article", keywords = "CpS, carbamoyl-phosphate synthetase", keywords = "HPr(Ser-P), serine phosphorylated HPr", keywords = "pI, isoelectric point", keywords = "μLC-ESI-IT-MS-MS, micro liquid chromatography coupled with electrospray ionization ion trap tandem mass spectrometry", keywords = "PpC, phosphoenolpyruvate carboxylase", keywords = "HPr(His-P), histidine phosphorylated HPr", abstract = " Streptococcus thermophilus is a major component of dairy starter cultures used for the manufacture of yoghurt and cheese. In this study, the CO2 metabolism of S. thermophilus DSM 20617T, grown in either a N2 atmosphere or an enriched CO2 atmosphere, was analysed using both genetic and proteomic approaches. Growth experiments performed in a chemically defined medium revealed that CO2 depletion resulted in bacterial arginine, aspartate and uracil auxotrophy. Moreover, CO2 depletion governed a significant change in cell morphology, and a high reduction in biomass production. A comparative proteomic analysis revealed that cells of S. thermophilus showed a different degree of energy status depending on the CO2 availability. In agreement with proteomic data, cells grown under N2 showed a significantly higher milk acidification rate compared with those grown in an enriched CO2 atmosphere. Experiments carried out on S. thermophilus wild-type and its derivative mutant, which was inactivated in the phosphoenolpyruvate carboxylase and carbamoyl-phosphate synthase activities responsible for fixing CO2 to organic molecules, suggested that the anaplerotic reactions governed by these enzymes have a central role in bacterial metabolism. Our results reveal the capnophilic nature of this micro-organism, underlining the essential role of CO2 in S. thermophilus physiology, and suggesting potential applications in dairy fermentation processes.", }