title: A model of proteolysis and amino acid biosynthesis for Lactobacillus delbrueckii subsp. bulgaricus in whey.
abstract: Lactobacillus delbrueckii subsp. bulgaricus 2038 (L. bulgaricus 2038) is a bacterium that is used as a starter for dairy products by Meiji Co., Ltd of Japan. Culturing L. bulgaricus 2038 with whey as the sole nitrogen source results in a shorter lag phase than other milk proteins under the same conditions (carbon source, minerals, and vitamins). Microarray results of gene expression revealed characteristics of amino acid anabolism with whey as the nitrogen source and established a model of proteolysis and amino acid biosynthesis for L. bulgaricus. Whey peptides and free amino acids are readily metabolized, enabling rapid entry into the logarithmic growth phase. The oligopeptide transport system is the primary pathway for obtaining amino acids. Amino acid biosynthesis maintains the balance between amino acids required for cell growth and the amount obtained from environment. The interconversion of amino acids is also important for L. bulgaricus 2038 growth.
authors.affiliation: Graduate School of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa, Kanagawa 252-0880, Japan. anannananna@hotmail.co.jp
authors.forename: Enuo
authors.initials: E
authors.lastname: Liu
authors.forename: Huajun
authors.initials: H
authors.lastname: Zheng
authors.forename: Pei
authors.initials: P
authors.lastname: Hao
authors.forename: Tomonobu
authors.initials: T
authors.lastname: Konno
authors.forename: Yao
authors.initials: Y
authors.lastname: Yu
authors.forename: Hisae
authors.initials: H
authors.lastname: Kume
authors.forename: Munehiro
authors.initials: M
authors.lastname: Oda
authors.forename: Zai-Si
authors.initials: ZS
authors.lastname: Ji
mesh_terms: D000596:Amino Acids / Q000096:biosynthesis*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D003470:Culture Media; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism; D005285:Fermentation; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D007218:Industrial Microbiology; D007564:Japan; D048668:Lactobacillus delbrueckii / Q000145:classification / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D008894:Milk Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D020411:Oligonucleotide Array Sequence Analysis; D059748:Proteolysis; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D000067816:Whey Proteins
chemical_list: D000596:Amino Acids; D001426:Bacterial Proteins; D003470:Culture Media; D004269:DNA, Bacterial; D008894:Milk Proteins; D012333:RNA, Messenger; D000067816:Whey Proteins