Vitamin B12 release through bacteriophage-mediated cell lysis of the marine bacterium Sulfitobacter sp. M39.

Sultana S, Bruns S, Pacheco-Valenciana A, Mehrshad M, Wilkes H, Simon M, Garcia S, Wienhausen G

ISME COMMUN. 5 (1) ycaf136 [2025-01-00; online 2025-08-29]

Vitamin B12 (B12) is an essential cofactor for vital metabolic processes in both prokaryotes and eukaryotes. De novo B12 biosynthesis is exclusively carried out by a modicum of prokaryotes, although being required by most organisms. Recently, it has been demonstrated that not all B12-prototrophic bacteria voluntarily share this vital cofactor and, therefore, are termed B12-retainers. Consequently, low biosynthesis potential and limited voluntary release lead to a large discrepancy between availability and demand for B12 in the ocean, indicating that release of B12 may be an important control. Hence, in this study, we examined a specific release process, cell lysis after phage infection. We isolated bacteriophages specific for the B12-prototrophic, yet B12-retainer bacterium Sulfitobacter sp. M39. The addition of the bacteriophages to a Sulfitobacter sp. M39 mono-culture led to a significant increase in virus-like particles, reduced bacterial growth, and quantifiable extracellular dissolved B12. When introducing bacteriophages to a co-culture comprising the host bacterium and the B12-auxotrophic diatom Thalassiosira pseudonana, we observed rapid response in the form of microalgal growth. Our results indicate that B12 is released as a result of bacteriophage-mediated cell lysis of Sulfitobacter sp. M39, enabling the growth of T. pseudonana in co-culture and possibly other microbes in nature. Therefore, we propose that bacteriophage-mediated cell lysis is a key mechanism for the release of essential metabolites, including vitamins, and given the estimated bacteriophage infection rates in the ocean, it plays a crucial role in the B-vitamin cycle in the marine environment.

Bioinformatics Support for Computational Resources [Service]

PubMed 40994829

DOI 10.1093/ismeco/ycaf136

Crossref 10.1093/ismeco/ycaf136

pmc: PMC12456174
pii: ycaf136