The Effect of clpP Gene Disruption on Cell Morphology, Growth, and the Ability to Synthesize Cellulose of Komagataeibacter xylinus E25.

Komagataeibacter species are the best producers of bacterial nanocellulose membranes (BNC)-amazing biomaterial with unique properties and applications in the medical and food industries. The molecular mechanisms of BNC synthesis control remain poorly understood and the need for BNC production and structure improvement is growing. Looking for the genes significant for biosynthesis, we studied the unexplored effect of ClpP proteolytic subunit inactivation on Komagataeibacter xylinus E25 cell morphology and production of BNC. A mutant with a disrupted clpP gene and a complemented strain were obtained. The colonies of the mutant cells, in contrast to the wild-type and complemented ones, were smaller, irregular, and were surrounded by a polymeric noncellulosic envelope. Additionally, the mutant cells were longer and organized in chains, showing different growth and production dynamics of BNC when grown under standard conditions. We also observed worse growth and production of BNC at 5 °C above optimal temperature and in the presence of increased levels of ethanol. E25 mutant cells were characterized by lower viability under stress conditions. The 3D microstructure of BNC displayed thicker fibers and denser packing and contained more hard-to-extract exopolysaccharides (HE-EPSs). Based on the outcomes, we conclude that the effect of ClpP on K. xylinus decreased resistance to stress and lowered the BNC production level.