A fermentative microbial community maintained in a 282-day continuous bioreactor experiment fed ultra-filtered milk permeate (UFMP), a low-value dairy coproduct. Originally inoculated from an acid-phase digester at the Nine Springs Wastewater Treatment Plant (Madison, WI). Metagenome-assembled genomes (MAGs) revealed functional partitioning between phyla: Actinobacteriota members (Olsenella, Bifidobacterium, Pauljensenia) degrade lactose via the Leloir pathway and bifid shunt, producing acetic, lactic, and succinic acids. Firmicutes members (Clostridium, Agathobacter) perform chain elongation via reverse beta-oxidation, converting lactic acid, ethanol, or lactose into butyric, hexanoic, and octanoic acids. This cross-feeding between Actinobacteriota (acid producers) and Firmicutes (chain elongators) forms the core metabolic network enabling conversion of dairy waste into renewable chemicals via the carboxylate platform.
Taxonomy
| Taxon | Ontology ID | Functional Roles | Abundance |
|---|---|---|---|
| Olsenella_B sp. (MAG ATO3) | NCBITaxon:133926 |
PRIMARY_DEGRADER
|
DOMINANT |
| Clostridium_B sp. (MAG CLOS1) | NCBITaxon:1485 |
SECONDARY_FERMENTER
|
DOMINANT |
| Pauljensenia sp. (MAG ACT2) | NCBITaxon:2767049 |
PRIMARY_DEGRADER
|
DOMINANT |
| Agathobacter rectalis (MAG LCO1) | NCBITaxon:1851376 |
SECONDARY_FERMENTER
|
DOMINANT |
| Bifidobacterium tibiigranuli (MAG BIF2) | NCBITaxon:1678 |
PRIMARY_DEGRADER
|
DOMINANT |
| RUG023 sp. (MAG SPH2) | NCBITaxon:203691 |
CROSS_FEEDER
|
DOMINANT |
| Bifidobacterium sp. (MAG BIF11) | NCBITaxon:1678 |
PRIMARY_DEGRADER
|
DOMINANT |
| Olsenella_B sp900119625 (MAG ATO6) | NCBITaxon:133926 |
PRIMARY_DEGRADER
|
DOMINANT |
| Bifidobacterium thermophilum (MAG BIF18) | NCBITaxon:1682 |
PRIMARY_DEGRADER
|
DOMINANT |
| Acidaminococcus sp. (MAG ACID1) | NCBITaxon:904 |
SECONDARY_FERMENTER
|
DOMINANT |
Ecological Interactions
Lactose Degradation to Organic Acids
CROSS_FEEDINGMetabolites: lactose (CHEBI:17716), acetic acid (CHEBI:15366), lactic acid (CHEBI:422), succinic acid (CHEBI:30031)
Evidence
-
PMID:37324413 - SUPPORT (IN_VITRO)"members of the Actinobacteriota phylum are important in the degradation of lactose, via the Leloir pathway and the bifid shunt, and the production of acetic, lactic, and succinic acids "
Chain Elongation to Medium-Chain Fatty Acids
CROSS_FEEDINGMetabolites: lactic acid (CHEBI:422), ethanol (CHEBI:16236), butyric acid (CHEBI:30772), hexanoic acid (CHEBI:30776), octanoic acid (CHEBI:28837)
Evidence
-
PMID:37324413 - SUPPORT (IN_VITRO)"members of the Firmicutes phylum contribute to the chain-elongation-mediated production of butyric, hexanoic, and octanoic acids, with different microbes using either lactose, ethanol, or lactic acid as the growth substrate "
Actinobacteriota-Firmicutes Cross-Feeding Network
CROSS_FEEDINGSource Taxon: Olsenella (Actinobacteriota)
Target Taxon: Clostridium (Firmicutes)
Metabolites: lactic acid (CHEBI:422)
Evidence
-
PMID:37324413 - SUPPORT (IN_VITRO)"members of the Actinobacteriota phylum are important in the degradation of lactose, via the Leloir pathway and the bifid shunt, and the production of acetic, lactic, and succinic acids "
Associated Datasets
| Dataset | Type | Repository | Accession |
|---|---|---|---|
|
Metagenome Sequencing
Shotgun metagenome sequencing data from the UFMP fermentation bioreactor used for MAG reconstruction and metabolic pathway analysis. |
METAGENOME | NCBI_BIOPROJECT | PRJNA768492 |
Environmental Factors
| Factor | Value | Unit |
|---|---|---|
| Temperature | 35 | degrees C |
| pH | 5.5 | N/A |
| Hydraulic Retention Time | 6 | days |
| Feed Substrate | Ultra-filtered milk permeate (UFMP) | N/A |
| Atmosphere | Anaerobic | N/A |