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Time‐resolved genetic responses of Lactococcus lactis to a dairy environment
Author(s) -
Bachmann Herwig,
De Wilt Leonie,
Kleerebezem Michiel,
Van Hylckama Vlieg Johan E. T.
Publication year - 2010
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/j.1462-2920.2010.02168.x
Subject(s) - lactococcus lactis , biology , starter , gene , cheese ripening , reporter gene , pseudogene , fermentation starter , bacteria , computational biology , gene expression , microbiology and biotechnology , genetics , food science , genome , lactic acid
Summary Lactococcus lactis is one of main bacterial species found in mixed dairy starter cultures for the production of semi‐hard cheese. Despite the appreciation that mixed cultures are essential for the eventual properties of the manufactured cheese the vast majority of studies on L. lactis were carried out in laboratory media with a pure culture. In this study we applied an advanced recombinant in vivo expression technology (R‐IVET) assay in combination with a high‐throughput cheese‐manufacturing protocol for the identification and subsequent validation of promoter sequences specifically induced during the manufacturing and ripening of cheese. The system allowed gene expression measurements in an undisturbed product environment without the use of antibiotics and in combination with a mixed strain starter culture. The utilization of bacterial luciferase as reporter enabled the real‐time monitoring of gene expression in cheese for up to 200 h after the cheese‐manufacturing process was initiated. The results revealed a number of genes that were clearly induced in cheese such as cysD , bcaP , dppA , hisC , gltA , rpsE , purL , amtB as well as a number of hypothetical genes, pseudogenes and notably genetic elements located on the non‐coding strand of annotated open reading frames. Furthermore genes that are likely to be involved in interactions with bacteria used in the mixed strain starter culture were identified.