Collecting samples of hydrogen oxidizing bacteria

Bugs
1

I recently came across this lovely video about Solar Foods shot last year, and around the 2:30 mark they show the co-founder collecting a sample in the Finnish forest. What I find really interesting is that he collects the sample from the mud underneath the water - as there is less oxygen there. Maybe something to keep in mind when we collect samples?

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Yes, I think we need to be targeting sample locations with high hydrogen concentrations and low organic carbon (or other energy sources)*. It’s interesting that he mentions “this is one of the places where we have been looking for the kind of samples to search for the organism”. Solein uses[1]"Xanthobacter sp. SoF1, a bacterium recently isolated from BalticSea shore sediment and deposited as VTT-E-19358"[2]

I also like his comment that if you didn’t kill them you’d need probiotic approval. I wonder if there’s a way that humans could ever safely consume a probiotic HOB consortium? A nightmare for regulators (given risk of contamination and pathogenic infection) but it would save a tonne of energy if you didn’t need to go full aseptic then pasteurise and/or spray dry.

And I loved the concept that their ice cream is Solein in it’s most plain form. Wouldn’t it be amazing if you could go straight from bioreactor to freezer!

*My GPT4o suggests:

The best strains of Hydrogen Oxidising Bacteria (HOB) are likely to be found in environments where they naturally thrive due to the presence of hydrogen and low levels of organic carbon. These environments often include:

1. Hydrothermal Vents

  • Why: These deep-sea locations are rich in hydrogen gas and minerals, creating an ideal environment for chemolithoautotrophic bacteria like HOB.
  • Examples: Mid-ocean ridges, such as the East Pacific Rise and Mid-Atlantic Ridge.

2. Volcanic and Geothermal Areas

  • Why: These regions release hydrogen gas through volcanic activity and host diverse microbial ecosystems.
  • Examples: Yellowstone National Park (USA), Icelandic geothermal fields, and Kamchatka (Russia).

3. Anoxic Sediments

  • Why: Anaerobic conditions combined with hydrogen gas production from microbial fermentation provide a suitable niche for HOB.
  • Examples: Wetlands, marshes, and lake sediments.

4. Soil Near Root Zones (Rhizosphere)

  • Why: Hydrogen is sometimes released as a byproduct of nitrogen fixation by root-associated bacteria, creating a microenvironment for HOB.
  • Examples: Leguminous plants like beans and clover.

5. Aquatic Environments with Gas Seeps

  • Why: Subaquatic seeps emit hydrogen and other gases, supporting microbial communities including HOB.
  • Examples: Methane seeps and cold seeps on continental shelves.

6. Industrial Hydrogen Production Sites

  • Why: HOB may colonize areas around industrial hydrogen leaks or emissions.
  • Examples: Refineries, hydrogen storage facilities, or fuel cell production sites.

7. Hot Springs

  • Why: Hydrogen released in these thermophilic environments provides energy for HOB communities.
  • Examples: Hot springs in New Zealand, Japan, and the USA.

8. Deep Subsurface Environments

  • Why: These environments often have natural hydrogen reservoirs due to geological processes such as serpentinization.
  • Examples: Deep mines, boreholes, or aquifers with hydrogen-rich rock formations.

Best Collection Strategies:

  • Environmental Sampling: Use sterile techniques to sample water, sediments, or soils from the locations mentioned above.
  • Enrichment Cultures: Isolate HOB by cultivating samples in minimal media with hydrogen as the sole energy source.
  • Molecular Techniques: Employ metagenomics and 16S rRNA sequencing to identify and characterize strains.

Focusing on these natural habitats is likely to yield diverse and potentially useful strains of HOB for research and application.

  1. S. HOLMSTRÖM and J.-P. Pitkänen, ‘Strains and processes for single cell protein or biomass production’, WO2021084159A1, May 06, 2021 Accessed: Jan. 10, 2025. [Online]. Available: WO2021084159A1 - Strains and processes for single cell protein or biomass production - Google Patents ↩︎

  2. K. Klinzing et al., ‘In vitro genotoxicological evaluation of protein-rich powder derived from Xanthobacter sp. SoF1’, Journal of Applied Toxicology, vol. 44, no. 9, pp. 1347–1360, 2024, doi: 10.1002/jat.4621. ↩︎