New publication: Engineering a Photoautotrophic Microbial Coculture toward Enhanced Biohydrogen Production

A new publication, with PROMICON’s support, examines a photoautotrophic microbial coculture community that harnesses the power of phototrophic microbes to enhance the production of bioenergy products while addressing environmental sustainability.

The phototrophic microbial communities, which naturally exist in light-exposed environments, play a critical role in global organic compound production by fixing carbon dioxide and nitrogen gases. With increasing energy demands and environmental challenges, these synthetic microbial consortia offer a promising alternative to traditional energy generation methods. By harnessing solar energy, water, and gases like CO2 and N2, they can efficiently produce valuable bioenergy products, such as biohydrogen and fatty acids.

However, creating stable synthetic microbial communities outside their natural habitat presents significant challenges. In such artificial environments, one strain could outcompete the others, leading to an imbalance that compromises the consortium’s functionality. Thus, developing strategies to maintain strain equilibrium and regulate the community’s overall activity is essential for optimising bioenergy production.

This study aimed to address these challenges by engineering a synthetic phototrophic coculture. By cocultivating Rhodopseudomonas palustris with either the wild-type Synechocystis sp. PCC 6803 or an engineered strain, Synechocystis_acs (which overproduces acetate), a community capable of producing biohydrogen and fatty acids through carbon and nitrogen fixation was created. Various light regulation strategies were applied, such as circadian light-dark and light-infrared illumination, to facilitate metabolic coordination and optimise coculture growth.

The results revealed that the engineered community could efficiently fix CO2 and N2, producing biohydrogen and fatty acids under controlled light conditions. This approach demonstrates a promising strategy for regulating and enhancing the performance of phototrophic microbial consortia, offering a potential pathway for sustainable bioenergy production. By integrating genetic engineering with light-based regulation, this research contributes to advancing the field of bioenergy and provides a model for future developments in microbial coculture systems.