Lactococcus lactis subsp. lactis strain:IMAU11823 Genome sequencing. Lactococcus lactis subsp. lactis strain:IMAU11823

Objective: Lactococcus lactis subsp. lactis IMAU11823 has excellent fermentation characteristics and can produce exopolysaccharide（EPS）, isolated from natural fermented dairy products jiaokou in Xilinguole, Inner Mongolia. In order to further study the mechanism for the production of EPS, it is necessary to sequence the strain and decipher its genome. Methods: The PacBio SMRT sequencing technique was used to sequence its whole gene sequences, then we assembled, predicted and annotations functional genes by bioinformatics methods, and the gene relate to the EPS biosynthesis were further explored. Results: A single circular chromosome consists of 2,458,520 bp with 35.2% GC content and three circular plasmids (The genome size and GC content were 127,965 bp, 35.7%；24,554 bp, 39.5% and 7,734 bp, 32.7%, respectively) were detected in L. lactis subsp. lactis IMAU11823. Further, the genome of L. lactis subsp. lactis IMAU11823 was related to lactose, mannitol, cellobiose, sucrose, fructose, mannose and galactose uptake system, and biosynthesis of four sugar nucleotides as well as an eps cluster epsRXCDBEF（GTF1）H（GTF2）JKM was involved in EPS biosynthesis were found to. Conclusion: The present study revealed the genomic characteristics and the potential mechanism for the synthesis of EPS of L. lactis subsp. lactis IMAU11823, providing a theoretical basis for the structural characteristics of EPS and laying a theoretical foundation for the strain in industrial application.