A defined thermophilic dairy fermentation community composed of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus. The two lactic-acid bacteria form the canonical yogurt starter association, where metabolite exchange accelerates milk acidification: S. thermophilus provides formate, carbon dioxide, and urease-dependent ammonia/carbon dioxide effects that stimulate the lactobacillus, while proteolytic activity of L. delbrueckii subsp. bulgaricus releases peptides and amino acids that support the more weakly proteolytic streptococcus.
Taxonomy
| Taxon | Ontology ID | Functional Roles | Abundance |
|---|---|---|---|
| Streptococcus thermophilus | NCBITaxon:1308 |
CROSS_FEEDER
SECONDARY_FERMENTER
|
N/A |
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| Lactobacillus delbrueckii subsp. bulgaricus | NCBITaxon:1585 |
PRIMARY_DEGRADER
CROSS_FEEDER
|
N/A |
|
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Ecological Interactions
Streptococcus Formate and Carbon Dioxide Support
CROSS_FEEDINGSource Taxon: Streptococcus thermophilus
Target Taxon: Lactobacillus delbrueckii subsp. bulgaricus
Metabolites: formate (CHEBI:15740), carbon dioxide (CHEBI:16526)
Biological Processes:
- fermentation (GO:0006113)
- interspecies interaction between organisms (GO:0044419)
Evidence
-
PMID:20889781 - SUPPORT (IN_VITRO)"S. thermophilus is suggested to provide L. bulgaricus with formic acid"
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PMID:20889781 - SUPPORT (IN_VITRO)"folic acid and carbon dioxide"
-
PMID:24936380 - SUPPORT (IN_VITRO)"earlier l-lactate and formate accumulation"
Lactobacillus Proteolytic Nitrogen Support
CROSS_FEEDINGSource Taxon: Lactobacillus delbrueckii subsp. bulgaricus
Target Taxon: Streptococcus thermophilus
Metabolites: peptide (CHEBI:16670), amino acid (CHEBI:33709)
Biological Processes:
- fermentation (GO:0006113)
- interspecies interaction between organisms (GO:0044419)
Evidence
-
PMID:20889781 - SUPPORT (IN_VITRO)"nonproteolytic S. thermophilus profits from the proteolytic action"
-
PMID:19114510 - SUPPORT (IN_VITRO)"implicated mainly in the metabolism of nitrogen"
Urease-Dependent Acidification Acceleration
MUTUALISMSource Taxon: Streptococcus thermophilus
Target Taxon: Lactobacillus delbrueckii subsp. bulgaricus
Biological Processes:
- fermentation (GO:0006113)
Evidence
-
PMID:30594386 - SUPPORT (IN_VITRO)"urease deficiency inhibits the fermentative acceleration of protocooperation"
-
PMID:30594386 - SUPPORT (IN_VITRO)"NH3 and CO2 that it generates"
Oxygen Removal by Streptococcus Thermophilus
COLONIZATION_FACILITATIONSource Taxon: Streptococcus thermophilus
Target Taxon: Lactobacillus delbrueckii subsp. bulgaricus
Biological Processes:
- fermentation (GO:0006113)
Evidence
-
PMID:24936380 - SUPPORT (IN_VITRO)"dissolved oxygen (DO) suppresses yogurt fermentation"
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PMID:24936380 - SUPPORT (IN_VITRO)"Nox of S. thermophilus 1131 contributes greatly to yogurt fermentation"
Associated Datasets
| Dataset | Type | Repository | Accession |
|---|---|---|---|
|
Exact-composition publication - urease in yogurt protocooperation
Study of S. thermophilus and L. delbrueckii subsp. bulgaricus strain combinations showing that urease supports acidification in the two-species yogurt starter community. |
PHENOTYPE | OTHER | PMID:30594386 |
|
Exact-composition publication - S. thermophilus 1131 and L. bulgaricus 2038
Study of oxygen removal and NADH oxidase in a yogurt starter composed of S. thermophilus 1131 and L. delbrueckii subsp. bulgaricus 2038. |
PHENOTYPE | OTHER | PMID:24936380 |
|
Exact-composition publication - S. thermophilus LMG 18311 and L. bulgaricus ATCC 11842
Transcriptomic and proteomic analysis of S. thermophilus LMG 18311 cocultured in milk with L. delbrueckii subsp. bulgaricus ATCC 11842. |
METATRANSCRIPTOME | OTHER | PMID:19114510 |
|
Exact-composition publication - mixed-culture transcriptome in milk
Mixed-culture transcriptome study of S. thermophilus CNRZ1066 and L. bulgaricus ATCC BAA-365 during batch mixed-culture growth in milk. |
METATRANSCRIPTOME | OTHER | PMID:20889781 |
|
Exact-composition publication - genomic protocooperation analysis
Comparative-genomics analysis of L. bulgaricus and S. thermophilus that frames yogurt manufacturing as a two-species protocooperative system. |
OTHER | OTHER | PMID:19395564 |
Environmental Factors
| Factor | Value | Unit |
|---|---|---|
| milk substrate | skim milk or milk used for thermophilic yogurt fermentation | N/A |
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| dissolved oxygen | dissolved oxygen suppresses fermentation; S. thermophilus removes oxygen through NADH oxidase | N/A |
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| ammonia and carbon dioxide from urease | urease-generated NH3 and CO2 affect yogurt acidification | N/A |
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