Diversity of Lactococcus lactis in undefined mixed dairy starter cultures revealed by comparative genome analyses and targeted amplicon sequencing of epsD.

Diversity of Lactococcus lactis in undefined mixed dairy starter cultures revealed by comparative genome analyses and targeted amplicon sequencing of epsD. Appl Environ Microbiol. 2017 Dec 08;: Authors: Frantzen CA, Kleppen HP, Holo H Abstract Undefined mesophilic mixed (DL) starter cultures are used in the production of continental cheeses and contain unknown strain mixtures of Lactococcus lactis and leuconostocs. The choice of starter culture affects the taste, aroma and quality of the final product. To gain insight into the diversity of Lactococcus lactis strains in starter cultures, we whole-genome sequenced 95 isolates from three different starter cultures. Pan-genomic analyses, which included 30 publically available complete genomes, grouped the strains into 21 subsp. lactis and 28 subsp. cremoris lineages. Only one of the 95 isolates grouped with previously sequenced strains, and the three starter cultures showed no overlap in lineage distribution. Culture diversity was assessed by targeted amplicon-sequencing using purR, a core gene, and epsD, present in 93 of the 95 starter culture isolates, but absent in most of the reference strains. This allowed unprecedented discrimination of starter culture Lactococcus lactis, and revealed substantial differences between the three starter cultures and compositional shifts during cultivation of cultures in milk.Importance In contemporary cheese production, standardized frozen seed stock ...
Source: Applied and Environmental Microbiology - Category: Microbiology Authors: Tags: Appl Environ Microbiol Source Type: research