Neocallimastix-Methanobrevibacter Xylanolytic Coculture

Community ID CommunityMech:000156

Ecological State ENGINEERED

Environment laboratory anaerobic rumen coculture
ENVO:01001405

A defined anaerobic rumen-derived coculture in which the xylan-degrading fungus Neocallimastix frontalis PNK2 is grown with the hydrogenotrophic archaeon Methanobrevibacter smithii on xylan. The methanogen removes fermentation products through interspecies hydrogen transfer, shifting fungal metabolism toward acetate formation and increasing xylan utilization and extracellular hemicellulase activities.

Taxonomy

Taxon	Ontology ID	Functional Roles	Abundance
Neocallimastix frontalis	NCBITaxon:4757	PRIMARY_DEGRADER	COMMON
PMID:16348244 - SUPPORT (IN_VITRO) "Neocallimastix frontalis PNK2"
Methanobrevibacter smithii	NCBITaxon:2173	SYNTROPHIC_PARTNER	COMMON
PMID:16348244 - SUPPORT (IN_VITRO) "in coculture with Methanobrevibacter smithii on xylan"

Ecological Interactions

Taxon

Cross-feeding

Mutualism

Syntrophy

Competition

Commensalism

Niche partitioning

Colonization facilitation

Strain competition

Predation

Interspecies Hydrogen Transfer During Xylan Fermentation

SYNTROPHY

Source Taxon: Neocallimastix frontalis

Target Taxon: Methanobrevibacter smithii

Metabolites: xylan (CHEBI:37686), dihydrogen (CHEBI:18276), acetate (CHEBI:30089)

Biological Processes:

xylan catabolic process (GO:0045493)
biological process involved in interspecies interaction between organisms (GO:0044419)

Evidence

PMID:16348244 - SUPPORT (IN_VITRO)

"metabolite profiles became acetogenic as a result of interspecies hydrogen transfer"
PMID:16348244 - SUPPORT (IN_VITRO)

"more acetate and less lactate were formed, while formate and hydrogen did not accumulate"

Methanogen-Stimulated Xylan Utilization

SYNTROPHY

Source Taxon: Methanobrevibacter smithii

Target Taxon: Neocallimastix frontalis

Metabolites: xylan (CHEBI:37686)

Biological Processes:

xylan catabolic process (GO:0045493)

Evidence

PMID:16348244 - SUPPORT (IN_VITRO)

"Both the rate and extent of xylan utilization were increased by coculturing"

Enhanced Extracellular Hemicellulase Activities

SYNTROPHY

Source Taxon: Methanobrevibacter smithii

Target Taxon: Neocallimastix frontalis

Metabolites: xylan (CHEBI:37686)

Biological Processes:

xylanase activity (GO:0009044)
xylan catabolic process (GO:0045493)

Evidence

PMID:16348244 - SUPPORT (IN_VITRO)

"marked increases in the specific activities of extracellular xylanase (up to fivefold)"
PMID:16348244 - SUPPORT (IN_VITRO)

"alpha-l-arabinofuranosidase (up to fivefold), and beta-d-xylosidase (up to sevenfold)"

Associated Datasets

Dataset	Type	Repository	Accession
Ruminal fungus-methanogen xylanolytic activity phenotypes Primary study reporting xylan utilization, extracellular enzyme activities, and metabolite profiles for anaerobic ruminal fungi grown with and without M. smithii.	PHENOTYPE	OTHER	PMID:16348244

Environmental Factors

Factor	Value	Unit
xylan substrate	xylan as the growth substrate	N/A
PMID:16348244 - SUPPORT (IN_VITRO) "were grown axenically or in coculture with Methanobrevibacter smithii on xylan"
anaerobic incubation with methanogenic partner	anaerobic coculture conditions	N/A
PMID:16348244 - SUPPORT (IN_VITRO) "Three different ruminal anaerobic fungi"

Growth Media

anaerobic xylan medium

Atmosphere ANAEROBIC

Preparation notes: Anaerobic ruminal fungi were grown axenically or in coculture with M. smithii using xylan as the principal polysaccharide substrate.

Evidence

PMID:16348244

"Three different ruminal anaerobic fungi, Neocallimastix frontalis PNK2, Sphaeromonas communis B7, and Piromonas communis B19, were grown axenically or in coculture with Methanobrevibacter smithii on xylan."

PMID:16348244

"For an N. frontalis-M. smithii coculture, the positive stimulation was maintained during an extended (18-day) incubation period"