Cited by 1,536Porphyrin Metabolism and DisordersFolate and B Vitamins ResearchAlgal biology and biofuel production

Algae acquire vitamin B12 through a symbiotic relationship with bacteria

Croft, Martin T., Lawrence, Andrew D., Raux-Deery, Evelyne, Warren, Martin J., Smith, Alison G.·2005·Nature

Abstract

Vitamin B12 (cobalamin) was identified nearly 80 years ago as the anti-pernicious anaemia factor in liver, and its importance in human health and disease has resulted in much work on its uptake, cellular transport and utilization. Plants do not contain cobalamin because they have no cobalamin-dependent enzymes. Deficiencies are therefore common in strict vegetarians, and in the elderly, who are susceptible to an autoimmune disorder that prevents its efficient uptake. In contrast, many algae are rich in vitamin B12, with some species, such as Porphyra yezoensis (Nori), containing as much cobalamin as liver. Despite this, the role of the cofactor in algal metabolism remains unknown, as does the source of the vitamin for these organisms. A survey of 326 algal species revealed that 171 species require exogenous vitamin B12 for growth, implying that more than half of the algal kingdom are cobalamin auxotrophs. Here we show that the role of vitamin B12 in algal metabolism is primarily as a cofactor for vitamin B12-dependent methionine synthase, and that cobalamin auxotrophy has arisen numerous times throughout evolution, probably owing to the loss of the vitamin B12-independent form of the enzyme. The source of cobalamin seems to be bacteria, indicating an important and unsuspected symbiosis.

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Crossref · 10.1038/nature04056

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  • Microalgae exude photosynthesized organics as dissolved organic carbon (DOC); heterotrophic bacteria assimilate them, and in return bacteria contribute to algal growth through generation of CO2, micronutrients such as Fe, vitamins, macronutrients specifically fixed N, and phytohormones.

    “Microalgae exude a part of the photosynthesized organics as dissolved organic carbon (DOC); these are assimilated by heterotrophic bacteria, and in return, bacteria contribute to algal growth through the generation of CO2, micronutrients (such as Fe), vitamins, macronutrients, specifically fixed N and phytohormones [15,17].”
  • The vitamin B12 producer Halomonas sp. can support the growth of the cobalamin-auxotroph Porphyridium purpureum, similarly to exogenous vitamin B12.

    “Croft et al. [15] found that the vitamin B12 producer Halomonas sp., isolated from non-axenic cultures of Amphidinium operculatum, can support the growth of the cobalamin-auxotroph Porphyridium purpureum, similarly to exogenous vitamin B12.”

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Authors
Croft, M. T., Lawrence, A. D., Raux-Deery, E., Warren, M. J., & Smith, A. G.
Affiliations
  • University of Cambridge (GB)
  • University of Kent (GB)
Corresponding author
Smith, Alison G.
Venue
Nature
Published
2005-11
Volume
438
Issue
7064
Pages
90-93
ISSN
  • 0028-0836 (ISSN-L)
  • 1476-4687
OpenAlex
W1980733427
Cited by
1,536
References
29
Citations by year
2026: 106 · 2025: 112 · 2024: 120 · 2023: 144 · 2022: 144 · 2021: 118 · 2020: 93 · 2019: 109 · 2018: 101 · 2017: 87 · 2016: 59 · 2015: 51 · 2014: 57 · 2013: 49 · 2012: 43
FWCI
6.02
Type
journal article
Language
en
Open access
closed
Locations
  • Nature (publishedVersion)
  • PubMed (publishedVersion)
  • Kent Academic Repository (University of Kent) (submittedVersion)
  • RePEc: Research Papers in Economics (submittedVersion)
  • ePrints Soton (University of Southampton) (submittedVersion)
Funders
  • Queen Mary University of London
  • Research Councils UK
  • European Commission
  • Biotechnology and Biological Sciences Research Council
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Porphyrin Metabolism and Disorders
  • Health Sciences › Medicine › Rheumatology › Folate and B Vitamins Research
  • Physical Sciences › Energy › Renewable Energy, Sustainability and the Environment › Algal biology and biofuel production
Keywords
vitamin B12, algae, microalgae, symbiosis, symbiotic bacteria, methionine synthase, cobalamin-dependent enzymes, algal metabolism, seaweed, vitamin B12 deficiency
MeSH terms
Bacteria, Symbiosis, 5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase, Vitamin B 12, Genome, Coculture Techniques, Halomonas, Genomics, Eukaryota

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