Cyanobacteria form the foundation of the trophic cascade of nearly all biospheres on the surface of our planet and are ubiquitous to every known environment. These unique and diverse organisms have recently come to the forefront of contemporary discussions on the sustainable production of fuels, pharmaceuticals, cosmetics, and plastics. This increase in attention is due to many factors including their high photosynthetic capacity, relatively minimalistic growth requirements, genetic tractability, and untapped potential for novel therapeutics. While direct engineering of cyanobacterial species has been the primary focus of present research trends, there is growing interest in utilizing cyanobacteria in the context of synthetic microbial consortia to accomplish similar biotechnological goals. This approach allows for the distribution of metabolic load amongst the different participating species and compartmentalization of specialties that in the context of cyanobacterial driven consortia could mean that the cyanobacteria fulfill the role of providing nutrients to other members of the consortia in the form of fixed carbon or nitrogen. The goal, in essence, would be to create a synthetic symbiotic or commensal/cross-feeding interaction between the cyanobacteria and the other members of the synthetic community. However, there are many considerations that need to be addressed when conceptualizing how artificial consortia might be applied on an industrial scale which include maintaining species specificity in these consortia, facilitating nutrient exchange between species, preventing invasion of contaminating microbes, enabling the use of contaminated water sources, and identification of compatible metabolisms. Here, I present my work to address many of these questions through: A) the development of a functional surface display system that allows for mediated binding of cyanobacteria to functionalized cells/particles, B) the expansion of the surface display system, C) the creation of a photosynthetic co-culture capable of remediating waste water contaminated with a xenobiotic, and D) the experimental evolution of a heterotrophic species in long term co-culture with alginate bead encapsulated cyanobacteria. These approaches were designed to both mimic naturally occurring microbial partnerships, which utilize spatial co-localization of symbiotic species to ensure partnership stability and ward off potential contaminants, and provide practical utility in an industrial context. Furthermore, this work lays the foundation for comprehensive study of how cell-cell adhesion and long-term co-evolution could influence symbiotic relationships between microbial organisms, with the potential to yield insights into the conditions that eventually led to the endosymbiotic event that gave rise to the chloroplasts found in eukaryotic photosynthetic species.
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