2.3 Strain engineering
The ackA and poxB gene were knocked out on the basis of Bgl4(BL21(DE3)ΔarcA ΔldhA ΔatoB ΔpflB ) (Zhao, Li, & Deng, 2018) and performed according to CRISPR-Cas9 engineering in E. coli(Jiang et al., 2015). The related sgRNA was designed and shown in Supplementary 3.