In silico analysis of amino acid biosynthesis and proteolysis in Lactobacillus delbrueckii subsp. bulgaricus 2038 and the implications for bovine milk fermentation.
The amino acid biosynthesis pathway and proteolytic system of Lactobacillus delbrueckii subsp. bulgaricus 2038 (L. bulgaricus 2038), a mainstay of large-scale yogurt production, were modeled based on its genomic sequence. L. bulgaricus 2038 retains more potential for amino acid synthesis and a more powerful proteolytic system than other L. bulgaricus strains, but favors amino acid uptake over de novo synthesis. Free amino acids and peptides in bovine milk provide the main nitrogen sources; whey is more important than casein for L. bulgaricus during fermentation. Free amino acids are imported by amino acid permeases and by ABC-type transport systems whereas exogenous oligopeptides are imported by ABC-type proteins only. Histidine is neither synthesized nor imported singly, which might explain why L. bulgaricus cannot grow in synthetic media.
Shanghai-MOST Key Laboratory of Health and Disease Genomics, Chinese National Human Genome Center at Shanghai, 250 Bi-Bo Road, Zhang Jiang Hi-Tech Park, Shanghai, 201203, China. zhenghj@chgc.sh.cn
Huajun
H
Zheng
Enuo
E
Liu
Pei
P
Hao
Tomonobu
T
Konno
Munehiro
M
Oda
Zai-Si
ZS
Ji
D018528:ATP-Binding Cassette Transporters / Q000378:metabolism; D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D001426:Bacterial Proteins / Q000378:metabolism; D002417:Cattle; D005285:Fermentation; D007218:Industrial Microbiology; D048668:Lactobacillus delbrueckii / Q000235:genetics / Q000378:metabolism*; D053858:Metabolic Networks and Pathways; D008892:Milk / Q000378:metabolism*; D010447:Peptide Hydrolases / Q000378:metabolism; D010455:Peptides / Q000378:metabolism; D015014:Yogurt
D018528:ATP-Binding Cassette Transporters; D000596:Amino Acids; D001426:Bacterial Proteins; D010455:Peptides; D010447:Peptide Hydrolases