Fig. 1

Schematic representation of deletion vector construction. a pCN3, a shuttle vector for C. saccharobutylicum NCP262 in which the antibiotic cassette of pKVM4 is replaced by the catP gene from pJIR750. b pCN6, a suicide vector to delete the hsdR1 gene, where the pE194ts replicon is replaced by hsdR1 homologous arms. c pCN8, where the homologous arms of pCN6 are replaced by those hsdR2. d pChN1, a deletion vector for the hsdR2 where the codBA operon genes of pCN8 are replaced by those from C. ljungdahlii. e pChN, a deletion vector cassette produced by removing the hsdR2 homologous arms from pChN1