The research was successful in terms of using the CRISPR-Cas9 system to induce programmable DSB at the pre-determined site on the cyanobacterial genome.

With the co-transformation of template DNA, the CRISPR- Cas9-induced DSB improved the homologous recombination efficiency, allowed for the use of lower amount of template DNA and shorter homology arms, and enhanced the chance of concomitant integration of gene cassettes into all chromosomes of PCC 7942, hence accelerating the process of obtaining homogeneous, stable recombinant strains.

The CRISPR-Cas9 system also enabled the simultaneous and precise gene knock-out and knock-in so as to improve the succinate production in PCC 7942.

The results justify the use of CRISPR-Cas9 for genome engineering and manipulation of metabolic pathways in cyanobacteria.