Recent progress and challenges in CRISPR-Cas9 engineered algae and cyanobacteria

Photosynthetic microorganisms like microalgae and cyanobacteria are quickly gaining recognition for their financial potential and have recently been subjected to research into metabolic manipulation to produce biofuels and different bio-based chemicals from CO2 and sunlight. CRISPR-Cas systems are presently the centre of attraction in synthetic biology research. Various cyanobacteria and algae species have been successfully edited using CRISPR-Cas9. However, many technical difficulties, such as chassis-organism-specific Cas9 toxicity, have delayed the progress of this tool for editing the genomes of diverse species of microalgae and cyanobacteria. CRISPR-Cas9 technology has enormous promises, and it has been employed to alter the metabolism of many algae and cyanobacteria. Advances in CRISPR-Cas9 technology and applications, as well as progress in CRISPR-based multiplex genome editing, the importance of traditional molecular tools in CRISPR biology, challenges in developing high-throughput mutant screening, and further improvements in genome-editing methods, have all been thoroughly discussed in order to make the genome engineering of algae and cyanobacteria more feasible. This review identifies important issues, suggests solutions, and highlights recent advances in genome editing in algae and cyanobacteria with the CRISPR-Cas9 system.