Presence of galactose in precultures induces lacS and leads to short lag phase in lactose-grown Lactococcus lactis cultures.

ABSTRACT: Lactose conversion by lactic acid bacteria is of high industrial relevance and consistent starter culture quality is of outmost importance. We observed that Lactococcus lactis using the high-affinity lactose-phosphotransferase system excreted galactose towards the end of the lactose consumption phase. The excreted galactose was re-consumed after lactose depletion. The lacS gene, known to encode a lactose permease with affinity for galactose, a putative galactose-lactose antiporter, was upregulated under the conditions studied. When transferring cells from anaerobic to respiration-permissive conditions, lactose-assimilating strains exhibited a long and non-reproducible lag phase. Through systematic preculture experiments, the presence of galactose in the precultures was correlated to short

SUBMITTER: Lorantfy B 

PROVIDER: S-EPMC6339885 | biostudies-literature | 2019 Jan

REPOSITORIES: biostudies-literature