Metabolic engineering of bacterial strains using CRISPR/Cas9 systems for biosynthesis of value-added products

Metabolically engineered bacterial strains are fast becoming the center of attraction in the biosynthesis of various bio-based ingredients. Currently, CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) with its associated RNA guided endonuclease (Cas9), is considered as the most promising tool that has brought a breakthrough in the genome editing approach. Although this versatile system originates from the immune systems of bacteria, its application in bacterial genome editing as an approach of metabolic engineering is still not so extensive. This review paper discusses the challenges, opportunities and application of CRISPR/Cas system in bacterial genome editing for biosynthesis of various value-added ingredients. The content of this paper mainly emphasizes Type II CRISPR/Cas9 system used for knock-in and knock-out of various target genes in the bacterial strains as a pre-requisite for increasing the production of bio-based materials.