Engineered artificial microbial consortium for L-lactic acid (LA) fermentation directly from undetoxified lignocellulosic (corncob) hydrolysates. A dual Bacillus coagulans (Heyndrickxia coagulans) system pairs a phenolic acid decarboxylase (PAD)-overexpressing biodetoxifying strain, DSM1-25280, with a high-yield LA producer, CC17B-1, and reaches 124.72 g/L LA from undetoxified hydrolysate via a sequential-inoculation division of labor. Multidimensional analysis supports a niche-succession model transitioning from biodetoxification-mediated commensalism to competitive exclusion. A sugar-metabolism-deficient engineered Pseudomonas putida KT2440 ZL added as a heterologous aromatic scavenger reinforces the system, raising the LA titer to 146.00 g/L at 98.9% yield.
Taxonomy
| Taxon | Ontology ID | Functional Roles | Abundance |
|---|---|---|---|
| Bacillus coagulans DSM1-25280 (PAD-overexpressing) — ontology label: Heyndrickxia coagulans | NCBITaxon:1398 · TaxonMech · TraitMech |
PRIMARY_DEGRADER
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N/A |
|
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| Bacillus coagulans CC17B-1 — ontology label: Heyndrickxia coagulans | NCBITaxon:1398 · TaxonMech · TraitMech |
SECONDARY_FERMENTER
|
N/A |
|
|||
| Pseudomonas putida KT2440 ZL — ontology label: Pseudomonas putida | NCBITaxon:303 · TaxonMech · TraitMech |
PRIMARY_DEGRADER
|
N/A |
|
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Ecological Interactions
The graph shows only explicitly linked interaction participants. Community members without an asserted participant link are omitted; membership alone does not imply an interaction.
Biodetoxification-Mediated Facilitation of CC17B-1
DSM1-25280 pretreatment lowers inhibitory phenolics and permits subsequent CC17B-1 fermentation of undetoxified corncob hydrolysate. The optimized dual-strain scheme adds 1 g/L DSM1-25280, then 3 g/L CC17B-1 after 12 h. CC17B-1 also contributes to detoxification; donor neutrality is not established. Accelerated vanillin loss accompanies PAD overexpression but is not demonstrated direct PAD catalysis.
Source Taxon: Bacillus coagulans DSM1-25280 (PAD-overexpressing)
Target Taxon: Bacillus coagulans CC17B-1
Metabolites: vanillin (CHEBI:18346 · MediaIngredientMech · CMMMech)
HYPOTHESIZED - detoxification may remove the selective advantage of the stress-tolerant DSM1-25280 strain and permit CC17B-1 dominance. CFU succession supports the proposed trade-off model but does not isolate resource competition from lactic-acid inhibition or loss of culturability.
Evidence
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PMID:42098792 - PARTIAL (IN_VITRO)"a strongly supported model of niche succession process within the system, transitioning from biodetoxification-mediated commensalism to competitive exclusion"
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PMID:42098792 - SUPPORT (IN_VITRO)"overexpression of PAD in the engineered strain DSM1-25280 not only enhanced tolerance to phenolic acids but also significantly accelerated vanillin degradation"
CC17B-1 Dominance and Hypothesized Exclusion of DSM1-25280
After 24 h in the optimized dual-strain culture, CC17B-1 CFU increased while DSM1-25280 CFU declined and became undetectable after 72 h. The proposed direction of exclusion is CC17B-1 toward DSM1-25280. HYPOTHESIZED resource competition and metabolic trade-offs may explain this pattern, but product inhibition is an explicit alternative and CFU measures culturability, not demonstrated extinction or real-time metabolic viability.
Source Taxon: Bacillus coagulans CC17B-1
Target Taxon: Bacillus coagulans DSM1-25280 (PAD-overexpressing)
Evidence
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PMID:42098792 - PARTIAL (IN_VITRO)"transitioning from biodetoxification-mediated commensalism to competitive exclusion"
Aromatic scavenging by P. putida KT2440 ZL reinforces LA fermentation
The three-strain protocol first incubates sugar-metabolism-deficient P. putida KT2440 ZL aerobically at 30 C for 12 h, then shifts to 50 C anaerobic DSM1-25280 fermentation and adds CC17B-1 after another 12 h. This staged treatment reached 146.00 g/L LA and 98.9% yield versus 124.72 g/L for the optimized dual culture. Aromatic scavenging is the proposed contribution; the comparison does not selectively isolate that mediator, donor neutrality or stable simultaneous three-strain coexistence.
Participating Taxa: Bacillus coagulans DSM1-25280 (PAD-overexpressing), Bacillus coagulans CC17B-1, Pseudomonas putida KT2440 ZL
Biological Processes:
- small molecule catabolic process (GO:0044282 · PathwayMech)
PARTIAL - aerobic ZL pretreatment may reduce recalcitrant aromatic toxicity and facilitate the subsequent anaerobic Bacillus relay. The staged treatment improves fermentation, but does not selectively establish aromatic removal as the sole mediator or equate the two temperature/oxygen stages.
Evidence
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PMID:42098792 - PARTIAL (IN_VITRO)"an enhanced three-strain co-culture system by incorporating a sugar-metabolism-deficient engineered Pseudomonas putida KT2440 ZL as a heterologous aromatic scavenger"
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PMID:42098792 - SUPPORT (IN_VITRO)"This system further elevated the LA titer to 146.00 g/L with a yield of 98.9%"
Knowledge gaps & discussions (1)
KNOWLEDGE_GAP OPEN What causes the DSM1-25280 culturability decline and the benefit of ZL pretreatment?
Resolve resource competition versus product inhibition with selective perturbations and viability measurements. Preserve the distinct DSM1-25280 and CC17B-1 labels despite their shared NCBITaxon ID. PAD-associated vanillin removal has an unresolved indirect mechanism. ZL aromatic mediation needs stage-matched controls and chemical measurements; no new nodes or arrows are required to express these limits. Vessel and medium-stage metadata remain under #1414.
Attaches to: ecological_interactions#Biodetoxification-Mediated Facilitation of CC17B-1, ecological_interactions#CC17B-1 Dominance and Hypothesized Exclusion of DSM1-25280, ecological_interactions#Aromatic scavenging by P. putida KT2440 ZL reinforces LA fermentation
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