Colanic acid has broad application
prospects in the food
and healthcare
market due to its excellent physical properties and biological activities.
In this study, we discovered that colonic acid production in Escherichia coli could be enhanced by regulating cardiolipin
biosynthesis. Single deletion of clsA, clsB, or clsC related to cardiolipin biosynthesis in E. coli MG1655 only slightly increased colonic acid production,
but double or triple deletion of these three genes in E. coli MG1655 increased colonic acid production up to 2.48-fold. Previously,
we have discovered that truncating lipopolysaccharide by deletion
of the waaLUZYROBSPGQ gene cluster and enhancing
RcsA by deletion of genes lon and hns can increase colonic acid production in E. coli. Therefore, these genes together with clsA, clsB, or/and clsC were deleted in E. coli, and all the resulting mutants showed increased
colonic acid production. The best colonic acid production was observed
in the mutant WWM16, which is 126-fold higher than in the control
MG1655. To further improve colonic acid production, the genes rcsA and rcsD1‑466
were
overexpressed in WWM16, and the resulting recombinant E. coli WWM16/pWADT could produce 44.9 g/L colonic acid, which is the highest
titer reported to date.