Fig. 4

Schematic representation of the C. saccharoperbutylacetonicum N1-4 (HMT) genomic region comprising both the sol operon (shown within a rectangle) and QSS5 genes (a) and transcriptional analyses of the sol operon (bld was used for the qRT-PCR test as a representative) in N1-4 (HMT) and various mutants (b). Gene names are the following: bld, butyraldehyde dehydrogenase (Cspa_c56880); ctfA, butyrate-acetoacetate CoA-transferase subunit A (Cspa_c56890); ctfB, butyrate-acetoacetate CoA-transferase subunit B (Cspa_c56900); adc, acetoacetate decarboxylase (Cspa_c56910); other gene names as shown in Fig. 1. Bacterial RNAs were extracted from the cell culture after 24 h cultivation in P2 medium. The reported value is mean ± SD. The asterisk indicates that the corresponding gene expression level in that particular strain was significantly different from the WT strain (P < 0.05)