Tiny Microbes with a Big Impact: The Role of Cyanobacteria and Their Metabolites in Shaping Our Future

Abstract

Cyanobacteria are among the first microorganisms to have inhabited the Earth. Throughout the last few billion years, they have played a major role in shaping the Earth as the planet we live in, and they continue to play a significant role in our everyday lives. Besides being an essential source of atmospheric oxygen, marine cyanobacteria are prolific secondary metabolite producers, often despite the exceptionally small genomes. Secondary metabolites produced by these organisms are diverse and complex; these include compounds, such as pigments and fluorescent dyes, as well as biologically-active compounds with a particular interest for the pharmaceutical industry. Cyanobacteria are currently regarded as an important source of nutrients and biofuels and form an integral part of novel innovative energy-efficient designs. Being autotrophic organisms, cyanobacteria are well suited for large-scale biotechnological applications due to the low requirements for organic nutrients. Recent advances in molecular biology techniques have considerably enhanced the potential for industries to optimize the production of cyanobacteria secondary metabolites with desired functions. This manuscript reviews the environmental role of marine cyanobacteria with a particular focus on their secondary metabolites and discusses current and future developments in both the production of desired cyanobacterial metabolites and their potential uses in future innovative projects.

Keywords: biotechnology; microalgae; natural products.

Figure 1

Environmental impact of photosynthetic microorganisms in aquatic systems. Different classes of photosynthetic microorganisms are found in aquatic and marine environments where they form the base of healthy food webs and participate in symbioses with other organisms. However, shifting environmental conditions can result in community dysbiosis, where the growth of opportunistic species can lead to harmful blooms and toxin production with negative consequences to human health, livestock and fish stocks. Positive interactions are indicated by arrows; negative interactions are indicated by closed circles on the ecological model.

Figure 2

Examples of various secondary metabolites and pigments structures produced by marine cyanobacteria.

Figure 3

(A) Bio Intelligent Quotient (BIQ)—The Clever Treefrog—The Algaehouse, housing-project at the IBA Hamburg. Idea, concept and authorship: SPLITTERWERK, Label for Fine Arts, Graz; Arup GmbH, Berlin; B+G Ingenieure Bollinger und Grohmann GmbH, Frankfurt; Immosolar GmbH, Hamburg. Photo by SPLITTERWERK 2013. (B) Urban Algae Façade prototype by Cesare Griffa and Carlo Ratti Associati; prototyping team: Matteo Amela, Federico Borello, Marco Caprani; technical support by Environment Park Spa, Fotosintetica & Microbiologica Srl; lighting by iGuzzini. Photos by Filippo Ferraris. 2014 Salone del Mobile, Milan, Italy. (C1) Process Zero Exterior: the eight-story, 1960s-era building is among the 362 million square feet of office space the GSA must retrofit to reduce greenhouse gases by 30 percent before the 2020 deadline. Image credit: HOK/Vanderweil. (C2) Process Zero Exterior Facade Detail: algae, housed in glass tubes covering the building’s exterior, filters wastewater, consumes carbon dioxide from the nearby highway and uses photosynthesis to produce energy. Image credit: HOK/Vanderweil. (C3) Concept image created for the Perth Photobioreactor Design and copyright to Tom Wiscombe architecture. (C4) The FMSA Tower concept project, a self-sustainable skyscraper. Design and copyright to Dave Edwards. All photographs and artwork reproduced with permission of the authors.