Nitrogen fixation in marine purple photosynthetic bacteria changes with carbon source

June 9, 2025

A step towards sustainable bioproduction

A collaborative research group from the RIKEN CSRS and Kyoto University has discovered that a marine purple non-sulfur photosynthetic bacterium alters its nitrogen fixation efficiency and metabolic pathways depending on the type of carbon source in the environment, also affecting cell growth.

Purple non-sulfur photosynthetic bacteria, such as Rhodovulum sulfidophilum, are gaining attention not only as agricultural fertilizers and aquaculture feed, but also as tools for producing biodegradable plastics. They possess both photosynthetic and nitrogen fixation metabolic pathways, enabling them to grow autotrophically using sunlight, carbon dioxide, and nitrogen in the environment. This offers a sustainable route for the production of biomass and useful compounds while reducing environmental impact. However, their slow growth under autotrophic conditions and the complex, poorly understood metabolic pathways have limited their broader application. In this study, researchers analyzed the nitrogen fixation efficiency and the incorporation of fixed nitrogen into various amino acids in Rhodovulum sulfidophilum under both autotrophic and heterotrophic conditions. They discovered that nitrogen metabolism is intricately regulated by the type of carbon source available, which directly affects cell growth. These findings are expected to contribute to the development of sustainable material production using purple non-sulfur photosynthetic bacteria.

 

Original article

Scientific Reports　DOI: 10.1038/s41598-025-03605-4

M. Suzuki, T. Shirai, S. R. Morey-Yagi, A. Kondo, K. Numata,

"Evaluation of nitrogen fixation in the marine purple photosynthetic bacterium Rhodovulum sulfidophilum under autotrophic and heterotrophic conditions".

Contact

Keiji Numata
Team Director
Biomacromolecules Research Team