Production of bacterial cellulose hydrogels with tailored crystallinity from Enterobacter sp. FY-07 by the controlled expression of colanic acid synthetic genes.

Hydrogels exhibit smart three-dimensional networks and extraordinary water-absorbing ability. To improve the water-holding capacity of bacterial cellulose hydrogels, the expression of a biosynthetic gene cluster of colanic acid, a water-soluble polysaccharide, was induced in Enterobacter sp. FY-07, which produces an abundance of bacterial cellulose hydrogel under aerobic and anaerobic fermentation conditions. The results indicated that in situ modified bacterial cellulose hydrogels with different crystallinities, rheological properties and water-holding capacities were produced by cultivating the engineered strain Enterobacter sp. FY-07::tac under different inducing conditions. The water-holding capacity of the modified bacterial cellulose hydrogel was enhanced by more than 1.7 fold compared to the hydrogel produced by Enterobacter sp. FY-07, and the networks of the modified bacterial cellulose hydrogel were densified but still clear. These results suggest that this in situ modification strategy endows bacterial cellulose hydrogels with improved properties and potentially expands their applications in biomedical fields and the food industry.