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 and reproducible lag phases in respiration-permissive main cultivations. For starter culture production, the presence of galactose during propagation of dairy strains can provide a physiological marker for short culture lag phase in lactose-grown cultures.

Lorantfy, B., Johanson, A., Faria-Oliveira, F., Franzen, C., Mapelli, V., Olsson, L. (2019). Presence of galactose in precultures induces lacS and leads to short lag phase in lactose-grown Lactococcus lactis cultures. JOURNAL OF INDUSTRIAL MICROBIOLOGY & BIOTECHNOLOGY, 46(1), 33-43 [10.1007/s10295-018-2099-0].

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

Mapelli V;
2019

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 and reproducible lag phases in respiration-permissive main cultivations. For starter culture production, the presence of galactose during propagation of dairy strains can provide a physiological marker for short culture lag phase in lactose-grown cultures.
Articolo in rivista - Articolo scientifico
Galactose; Galactose–lactose antiporter; Lactococcus lactis; Lag phase; Starter cultures;
English
33
43
11
Lorantfy, B., Johanson, A., Faria-Oliveira, F., Franzen, C., Mapelli, V., Olsson, L. (2019). Presence of galactose in precultures induces lacS and leads to short lag phase in lactose-grown Lactococcus lactis cultures. JOURNAL OF INDUSTRIAL MICROBIOLOGY & BIOTECHNOLOGY, 46(1), 33-43 [10.1007/s10295-018-2099-0].
Lorantfy, B; Johanson, A; Faria-Oliveira, F; Franzen, C; Mapelli, V; Olsson, L
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/369025
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