Biocatalysis in Green and Blue: Cyanobacteria

• Published in: Trends in biotechnology (Regular ed.) Vol. 39; no. 9; pp. 875 - 889
• Main Authors: Jodlbauer, Julia, Rohr, Thomas, Spadiut, Oliver, Mihovilovic, Marko D., Rudroff, Florian
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.09.2021; Elsevier Limited
• Subjects: Binding sites; Biocatalysts; Biotechnology; Biotransformation; Carbon; Carbon dioxide; Carbon sources; Catalysis; Chemicals; Cloning; Cyanobacteria; Enzymes; Gene expression; Genetic engineering; industrial application; Metabolism; photobiocatalysis; photosynthesis; phototrophic metabolism; Productivity; Prokaryotes; Proteins; Sustainable production; whole-cell biotransformation; phototrophic metabolism; whole-cell biotransformation; photosynthesis; photobiocatalysis; cyanobacteria; industrial application
• ISSN: 0167-7799; 1879-3096
• DOI: 10.1016/j.tibtech.2020.12.009

Recently, several studies have proven the potential of cyanobacteria as whole-cell biocatalysts for biotransformation. Compared to heterotrophic hosts, cyanobacteria show unique advantages thanks to their photoautotrophic metabolism. Their ability to use light as energy and CO2 as carbon source promises a truly sustainable production platform. Their photoautotrophic metabolism offers an encouraging source of reducing power, which makes them attractive for redox-based biotechnological purposes. To exploit the full potential of these whole-cell biocatalysts, cyanobacterial cells must be considered in their entirety. With this emphasis, this review summarizes the latest developments in cyanobacteria research with a strong focus on the benefits associated with their unique metabolism. Remaining bottlenecks and recent strategies to overcome them are evaluated for their potential in future applications. Cyanobacteria use photosynthesis to harvest the Sun’s energy to bind atmospheric CO2 and accumulate biomass. This ability renders cyanobacteria interesting hosts for sustainable industrial processes.The photoautotrophic metabolism allows a constant supply with oxygen and NADPH, and so overcoming limitations, often faced in biotransformation with heterotrophic hosts.Compared to established biocatalysis hosts, cyanobacteria lag several years of development. Exploitation of their metabolism, especially of the photosynthesis apparatus, still shows room for improvement.Many aspects for whole-cell catalysis have not been investigated carefully enough, including mass transfer of substrate and product or tolerance towards stressors, such as solvents or ROS.Novel photo-bioreactor concepts and also new, and more efficient strains must be introduced to achieve economically feasible production.