PNNL

The Science

Just as humans rely on communities to thrive, microscopic organisms team up in nature to survive and flourish. Scientists have now uncovered surprising similarities between engineered microbial partnerships and natural ones, providing new insights into how microbes work together. Using an innovative bioreactor system with special membranes that keep different microbes separated while allowing them to exchange chemical messages, researchers studied the interaction between light-harvesting engineered cyanobacteria and single-celled fungi or yeast. Despite never meeting in nature, these microbes developed a remarkably efficient exchange system: the cyanobacteria converted sunlight and CO₂ into sugars, while the yeast transformed these sugars into compounds called sugar alcohols. This mirrors the same chemical conversation found in lichens—the widespread natural partnerships between fungi and photosynthetic organisms that create the colorful patches on rocks and tree bark. This discovery is part of Pacific Northwest National Laboratory's Predictive Phenomics Initiative, or PPI, and opens new possibilities for designing microbial teams that could help produce sustainable chemicals or clean up environmental pollutants by better understanding how microorganisms naturally cooperate and communicate.

The Impact

This research provides a new way to study and engineer microbial partnerships for biotechnology applications and also offers insights into metabolic exchanges in natural microbial communities. By comparing membrane-separated and direct co-cultivation approaches, researchers can now capture elusive metabolic exchanges that are typically difficult to measure in traditional studies. Understanding these interactions is crucial for designing synthetic microbial communities that could help produce sustainable chemicals and materials or remove pollutants from the environment. Furthermore, the observed sugar-for-sugar alcohol exchange patterns suggest that interactions between phototrophs and heterotrophs may be shaped by fundamental aspects of their core metabolism, as revealed by similar patterns across different partnerships, regardless of their evolutionary history. 

Summary

Results of this study have significant implications for understanding both natural microbial communities and designing synthetic ones. Researchers studied metabolic exchanges between two organisms, using both direct co-cultivation and membrane-separated bioreactors. This combined approach revealed detailed patterns of nutrient exchange between the partnered organisms and demonstrated that these engineered microbes interact in ways that mirror natural cyanolichen relationships. The membrane bioreactor system revealed the directionality of metabolite fluxes by capturing concentration gradients between species and identifying rapidly consumed compounds that would be difficult to detect in traditional mixed cultures. These insights can help advance the development of microbial consortia for sustainable biotechnology applications.

PNNL Contacts

• Pavlo Bohutskyi, pavlo.bohutskyi@pnnl.gov, PNNL
• Kyle Pomraning, kyle.pomraning@pnnl.gov, PNNL

Funding

The research described in this paper is part of the Predictive Phenomics Initiative at Pacific Northwest National Laboratory (PNNL) and conducted under the Laboratory Directed Research and Development Program. PNNL is a multiprogram national laboratory operated by Battelle for the Department of Energy under Contract No. DE-AC05-76RL01830.