Designing Microbial Communities For Enhanced Biohydrogen Production

Phototrophic microbial communities – groups of tiny organisms whose energy for growth comes from light – play a significant role in global primary production by absorbing carbon dioxide and nitrogen gas. With the growing challenges of energy demands and environmental concerns, researchers are exploring scientifically designed (synthetic) phototrophic communities as a promising alternative to traditional energy generation methods. These consortia can efficiently convert CO₂ and N₂ gases, along with water and solar energy, into bioenergy products, offering a potential solution to today’s energy and sustainability problems. In this context, the development of synthetic phototrophic communities has attracted increased attention due to their ability to divide tasks among different species, allowing them to function more efficiently and remain stable. However, challenges remain, particularly in maintaining balance among strains and ensuring stable performance in environments that do not replicate the complex natural conditions in which these consortia typically thrive. To address these challenges, recent PROMICON studies have focused on how cyanobacteria interact with purple nonsulfur bacteria (PNSB). These bacteria, including Rhodopseudomonas palustris (R. palustris), have shown potential in producing biohydrogen and lipids by capturing nitrogen in oxygen-free environments. Nevertheless, a key limitation is that they need a carbon-based food source (e.g., acetate) to produce energy. A promising approach to overcome this issue involves growing R. palustris with cyanobacteria, which can pull carbon dioxide from the air and turn it into the organic carbon that R. palustris needs to thrive.