5 Conclusions
Intracellular accumulation of c-di-GMP in Z. mobilis through
biosynthesis and degradation catalyzed by enzymes with DGC and PDE
activities activates the biosynthesis of cellulose fibrils for the
bacterial cells to self-flocculate with significant advantages in
industrial production. Compared to the overexpression of proteins with
DGC activity for synthesizing more c-di-GMP from GTP, deactivation of
PDE activity to compromise c-di-GMP degradation is preferred for
intracellular accumulation of the signal molecule, since this strategy
would exert less perturbation on intracellular processes involved with
or regulated by GTP. This study provides insights into the regulation of
c-di-GMP on the morphological shift in Z. mobilis from
unicellular cells to multicellular flocs, as well as guidelines for
engineering unicellular strains from this species and other bacteria
with the self-flocculating phenotype through rational design. Moreover,
this study provides a basis for exploring the mechanism underlying
c-di-GMP metabolism in Z. mobilis and its regulation of other
intracellular processes.