Gulf of Mexico Oil-Degrading Consortium

GC-MS with an abiotic-control baseline measured C8-C38 n-alkane depletion in the four-strain consortium and individual cultures. Consortium values reached about 60% at day 30 and about 45% at day 75; chain-length fractions differed, and time-dependent abiotic loss of shorter alkanes affects these relative estimates. These measurements support hydrocarbon transformation, not complete mineralization, obligatory niche partitioning or strain-resolved in-consortium flux. Similar monoculture preferences and MetaMIS predictions do not assign the consortium result exclusively to Pseudomonas or Alcanivorax.

Participating Taxa: Pseudomonas sp. GOM, Halopseudomonas aestusnigri GOM5, Paenarthrobacter sp. GOM3, Alcanivorax sp. GOM

Metabolites: alkane (CHEBI:18310 · MediaIngredientMech · CMMMech)

Biological Processes:

• alkane catabolic process (GO:0043448 · PathwayMech)

Evidence

• doi:10.3389/fmars.2022.962071 - SUPPORT (IN_VITRO)
  "We also measured biodegradation levels by Gas Chromatography/Mass Spectrometry (GC-MS) observing 12 polyaromatic hydrocarbons (PAHs) degradation analyzed and n-alkanes degradation with a preference for specific chain length"

GC-MS monitored 12 aromatic analytes, with different susceptibilities; not all 12 were substantially biodegraded. The consortium aggregate PAH estimate reached about 16% at day 75 relative to the abiotic baseline. The main text identifies fluorene, dibenzothiophene, methylated phenanthrenes and pyrene among susceptible compounds, while others were hardly biodegraded. This does not establish generic phenanthrene degradation, complete mineralization or a necessary division of labor. The canonical four participants identify the assayed consortium, not four proven owners of each degradation reaction.

Participating Taxa: Pseudomonas sp. GOM, Halopseudomonas aestusnigri GOM5, Paenarthrobacter sp. GOM3, Alcanivorax sp. GOM

Metabolites: fluorene (CHEBI:28266 · MediaIngredientMech · CMMMech), dibenzothiophene (CHEBI:23681 · MediaIngredientMech · CMMMech), pyrene (CHEBI:39106 · MediaIngredientMech · CMMMech)

Evidence

• doi:10.3389/fmars.2022.962071 - SUPPORT (IN_VITRO)
  "We also measured biodegradation levels by Gas Chromatography/Mass Spectrometry (GC-MS) observing 12 polyaromatic hydrocarbons (PAHs) degradation analyzed and n-alkanes degradation with a preference for specific chain length"

After 75 days, gravimetric light-crude-oil removal was about 62% in the Plackett-Burman-selected four-strain consortium versus about 25-39% in individual cultures. The authors explicitly did not subtract abiotic-control removal from these gross percentages, unlike the baseline used for GC-MS biodegradation. Both monocultures and consortium started at 1e8 CFU/mL per strain, so total starting CFUs were higher in the consortium; this is not a total-inoculum-matched synergy test. Stable relative abundance after day 7 and inferred MetaMIS interactions suggest possible cooperation, not directly demonstrated niche partitioning or the mechanism of this comparative endpoint. Neither the n-alkane nor PAH percentage alone selectively explains the gross-removal advantage.

Participating Taxa: Pseudomonas sp. GOM, Halopseudomonas aestusnigri GOM5, Paenarthrobacter sp. GOM3, Alcanivorax sp. GOM

Metabolites: alkane (CHEBI:18310 · MediaIngredientMech · CMMMech)

Evidence

• doi:10.3389/fmars.2022.962071 - SUPPORT (IN_VITRO)
  "Individually, bacterial oil removal by these microorganisms was evaluated by gravimetry, reaching 39% at maximum after 75 days, whereas in consortium it was ~62%."