Fig. 4

The application of CRISPR-Cas9 system for genome engineering in B. subtilis. a Diagram of the iterative genome editing procedure. b Sanger sequencing analysis of integrated site. c Colony PCR was performed to verify the knockout of epr gene and bpr gene. Lane 1: The PCR product of wild type (1551 bp); Lane 2: The PCR product of mutant type (1040 bp); Lane 3: The PCR product of wild type (1517 bp); Lane 4: The PCR product of mutant type (1008 bp). d Effect of diverse hosts on Douchi fibrinolytic enzyme production