Genomic Analysis Of Lactobacillus Delbrueckii Subsp. Bulgaricus Strain 2038

Lactobacillus delbrueckii subsp. bulgaricus is an important species of Lactic Acid Bacteria (LAB) used for cheese and yogurt fermentation. There was no genomic sequence for any industrial strains of Lb. bulgaricus available besides that of two academic strains. The genome of Lb. bulgaricus 2038 that has been employed for manufacturing yogurt since 1989 by Meiji Dairies Corporation, was completely sequenced and annotated.Lb. bulgaricus 2038 displays properties common for Lb. bulgaricus strains but favorable or essential for industrial applications, including abundant proteolytic system, high efficient lactate production, low flavor compounds production, acid stress tolerance, protocooperation with Streptococcus thermophilus, and degenerated amino acid biosynthetic capacity. Comparative genomic analysis against the two academic strains also identified 294 genes as Lb. bulgaricus 2038 specific, endowing this strain with specific features for yogurt production, such as extra-capabilities in lysine biosynthesis, EPS production, salvage formate production, aspartate-related intermediate metabolism, two complete typeâ…¡RM systems and more power proteolytic capacity over the academic strains.Analysis of gene evolution as well as phylogenetic analysis illustrated that gene loss was a common phenomenon in evolution of Lb. bulgaricus strains. Genetically, Lb. bulgaricus 2038 seems closer to the common ancestor than the other two academic strains. A strict maintenance process of Lb. bulgaricus 2038 for industrial purposes apparently slowed down the genome decay and sustained a gene network that ensures the optimal suitability for industrial production of yogurt.