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Microbial interactions shape cheese flavour formation.

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Zorrilla, Francisco 
Kjærbølling, Inge 
Blasche, Sonja 


Cheese fermentation and flavour formation are the result of complex biochemical reactions driven by the activity of multiple microorganisms. Here, we studied the roles of microbial interactions in flavour formation in a year-long Cheddar cheese making process, using a commercial starter culture containing Streptococcus thermophilus and Lactococcus strains. By using an experimental strategy whereby certain strains were left out from the starter culture, we show that S. thermophilus has a crucial role in boosting Lactococcus growth and shaping flavour compound profile. Controlled milk fermentations with systematic exclusion of single Lactococcus strains, combined with genomics, genome-scale metabolic modelling, and metatranscriptomics, indicated that S. thermophilus proteolytic activity relieves nitrogen limitation for Lactococcus and boosts de novo nucleotide biosynthesis. While S. thermophilus had large contribution to the flavour profile, Lactococcus cremoris also played a role by limiting diacetyl and acetoin formation, which otherwise results in an off-flavour when in excess. This off-flavour control could be attributed to the metabolic re-routing of citrate by L. cremoris from diacetyl and acetoin towards α-ketoglutarate. Further, closely related Lactococcus lactis strains exhibited different interaction patterns with S. thermophilus, highlighting the significance of strain specificity in cheese making. Our results highlight the crucial roles of competitive and cooperative microbial interactions in shaping cheese flavour profile.


Acknowledgements: We would like to thank Mads Bennedsen for his efforts in funding acquisition and also in project management, together with Karsten Hellmuth and Eric Johansen. We thank Kosai Al-Nakeeb, Anna Koza, Martin Abel-Kistrup and Jacbo Bælum for their significant contributions to the sequencing and assembly of the genomes of individual strains. We thank Lisandra Zepeda and Ida Bærholm Schnell for their help with cheese sampling. Finally, we thank Gunnar Øregaard for providing acidification data for the individual strains and Jannik Vindeloev and Ana Rute Neves for helpful discussions. This project has received funding from Innovation Fund Denmark (Grand Solution grant no. 6150-00033B; FoodTranscriptomics) and Chr. Hansen A/S. C.M acknowledges support from the Dutch Research Council, as part of the MiCRop Consortium (NWO/OCW grant no. 024.004.014). K.R.P. acknowledges support from the European Research Council (ERC) under the European Union’s Horizon 2020 Research and Innovation Program (Grant agreement no. 866028).

Funder: EC | EC Seventh Framework Programm | FP7 Ideas: European Research Council (FP7-IDEAS-ERC - Specific Programme: "Ideas" Implementing the Seventh Framework Programme of the European Community for Research, Technological Development and Demonstration Activities (2007 to 2013)); doi:; Grant(s): 866028


Animals, Cheese, Acetoin, Diacetyl, Lactococcus lactis, Streptococcus thermophilus, Fermentation, Milk, Food Microbiology

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Nat Commun

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Springer Science and Business Media LLC
European Commission Horizon 2020 (H2020) ERC (866028 ModEM)