CRISPR-Based Technologies for Metabolic Engineering in Cyanobacteria

• Published in: Trends in biotechnology (Regular ed.) Vol. 36; no. 10; pp. 996 - 1010
• Main Authors: Behler, Juliane, Vijay, Dhanya, Hess, Wolfgang R., Akhtar, M. Kalim
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.10.2018; Elsevier Limited
• Subjects: Bacteria; biotechnology; Carbon; Carbon dioxide; Carbon Dioxide - metabolism; Cas; Chemicals; Clustered Regularly Interspaced Short Palindromic Repeats; CRISPR; CRISPRi; Cyanobacteria; Cyanobacteria - genetics; Cyanobacteria - metabolism; Deoxyribonucleic acid; DNA; Efficiency; Gene Editing - methods; Gene expression; Gene regulation; Genes; Genetic engineering; Genome editing; Genomes; green economy; Industrial Microbiology - methods; Metabolic engineering; Metabolic Engineering - methods; Metabolism; Microorganisms; multiplex; Mutation; Organic Chemicals - metabolism; Organic chemistry; Photosynthesis; Plasmids; Recombination, Genetic; Transcription; green economy; biotechnology; Cas; CRISPRi; multiplex; photosynthesis
• ISSN: 0167-7799; 1879-3096
• DOI: 10.1016/j.tibtech.2018.05.011

In metabolic engineering, the production of industrially relevant chemicals, via rational engineering of microorganisms, is an intensive area of research. One particular group of microorganisms that is fast becoming recognized for their commercial potential is cyanobacteria. Through the process of photosynthesis, cyanobacteria can use CO2 as a building block to synthesize carbon-based chemicals. In recent years, clustered regularly interspaced short palindromic repeats (CRISPR)-dependent approaches have rapidly gained popularity for engineering cyanobacteria. Such approaches permit markerless genome editing, simultaneous manipulation of multiple genes, and transcriptional regulation of genes. The drastically shortened timescale for mutant selection and segregation is especially advantageous for cyanobacterial work. In this review, we highlight studies that have implemented CRISPR-based tools for the metabolic engineering of cyanobacteria. Cyanobacteria are appealing photosynthetic hosts for chemical production that can be genetically manipulated to direct the native metabolic flux toward target chemicals of interest. CRISPR/Cas9 and CRISPR/Cas12a enable metabolic engineers to modify the genomes of cyanobacteria with gene substitutions, markerless point mutations, and gene knockouts and knock-ins with improved efficiency. The repression of native genes via CRISPRi affords a practical way of reducing the flux through competing metabolic pathways and directing it toward the target chemical. Syntheses of a range of industrial target chemicals have been demonstrated in cyanobacteria. To further diversify target chemicals and meet the demands of industry, attention needs also to be given to target chemicals that depend on metabolic pathways with poor flux or involve more complex metabolic routes.