Towards a circular economy through microbial stability and in situ cultivation in a photobioreactor - chicken coop system

Finding sustainable systems that minimize waste and maximize resource efficiency especially in agriculture is a major challenge for circular economy. In this context, biological systems such as photobioreactors offer an attractive way to convert under-utilized nutrient streams such as CO2 into useful biomass products, such as photosynthetic microorganisms (PMOs) like Spirulina (Cyanobacteriota).

In this context, we investigated microbial interactions and community stability in an integrated photobioreactor-chicken coop system, where waste and nutrients were retained, to enable closed loop operations.

For this, samples taken from the photobioreactor at different timepoints were analyzed by metagenomics to evaluate the taxonomic composition and metabolic potential. First analysis demonstrated the impact of chicken house exhaust on the cyanobacterial culture via CO2 fixation and provided insights into NH3 metabolism. Taxonomic classification of the microbial community suspended in the photobioreactor revealed a predominance of bacterial organisms before aeration, with a notable shift to a more diverse community, including eukaryotic species, after exposure to chicken coop exhaust. ... mehr

In perspective we integrated a novel macroporous material into the system to allow direct monitoring of microbial dynamics. This will provide further valuable insights into microbial interactions in this particular context and allow us to directly assess community stability. Understanding community stability is essential to run integrated, closed-loop biological production systems. It illustrates how microbiome research can contribute to circular economy and serves as a precursor for possible integration into biological systems for resource efficient and sustainable solutions.