Synthetic biology in marine cyanobacteria: Advances and challenges

Abstract

The current economic and environmental context requests an accelerating development of sustainable alternatives for the production of various target compounds. Biological processes offer viable solutions and have gained renewed interest in the recent years. For example, photosynthetic chassis organisms are particularly promising for bioprocesses, as they do not require biomass-derived carbon sources and contribute to atmospheric CO2 fixation, therefore supporting climate change mitigation. Marine cyanobacteria are of particular interest for biotechnology applications, thanks to their rich diversity, their robustness to environmental changes, and their metabolic capabilities with potential for therapeutics and chemicals production without requiring freshwater. The additional cyanobacterial properties, such as efficient photosynthesis, are also highly beneficial for biotechnological processes. Due to their capabilities, research efforts have developed several genetic tools for direct metabolic engineering applications. While progress toward a robust genetic toolkit is continuously achieved, further work is still needed to routinely modify these species and unlock their full potential for industrial applications. In contrast to the understudied marine cyanobacteria, genetic engineering and synthetic biology in freshwater cyanobacteria are currently more advanced with a variety of tools already optimized. This mini-review will explore the opportunities provided by marine cyanobacteria for a greener future. A short discussion will cover the advances and challenges regarding genetic engineering and synthetic biology in marine cyanobacteria, followed by a parallel with freshwater cyanobacteria and their current genetic availability to guide the prospect for marine species.

Pleiotropic effects of PipX, PipY, or RelQ overexpression on growth, cell size, photosynthesis, and polyphosphate accumulation in the cyanobacterium Synechococcus elongatus PCC7942

“…Cyanobacteria have evolved sophisticated systems to maintain the homeostasis of carbon/nitrogen assimilation (reviewed by Zhang et al, 2018 ; Forchhammer and Selim, 2020 ), the two most abundant elements in all living forms. Therefore, understanding the regulatory mechanisms controlling their metabolic balance is of paramount importance for environmental sustainability and biotechnological applications ( Bougarde and Stensjö, 2022 ).…”

Harnessing photosynthetic microorganisms for enhanced bioremediation of microplastics: A comprehensive review

“…Photosynthesis is a biological process that utilises light energy to convert inorganic carbon into organic matter: photoautotrophic microorganisms generally have high photosynthetic and metabolic capacities and can produce a variety of valuable metabolites, such as lipids, carbohydrates, pigments, and proteins [ [181] , [182] , [183] ]. By exploiting the coupling with the energy obtained using available light via photosynthesis, the capability to fix CO 2 , and the ability of selected enzymes to produce desired molecules, microalgae and cyanobacteria may prove to be more advantageous and sustainable as hosts for the photobiocatalytic reactions by removing the need for the external addition of co-factors.…”

Current Metabolic Engineering Strategies for Photosynthetic Bioproduction in Cyanobacteria

“…Moreover, Prochlorococcus possesses some unique features amongst cyanobacteria, such as a photosynthetic apparatus composed of the divinyl derivatives of chlorophyll a and b (Chl-a 2 and Chl-b 2 ), a photosystem closer to that present in green plants and algae [ 73 ] and the ability to generate the volatile hemiterpenoid isoprene [ 75 ]. Although it has attractive biotechnological features, it is recalcitrant to DNA transfer and to growing axenically on solid media [ 76 , 77 ].…”