Enhancement of Inhibition of the Pseudomonas sp. Biofilm Formation on Bacterial Cellulose-Based Wound Dressing by the Combined Action of Alginate Lyase and Gentamicin.

Bacterial biofilms generally contribute to chronic infections, including wound infections. Due to the antibiotic resistance mechanisms protecting bacteria living in the biofilm, they are a serious problem in the wound healing process. To accelerate the wound healing process and avoid bacterial infection, it is necessary to select the appropriate dressing material. In this study, the promising therapeutic properties of alginate lyase (AlgL) immobilised on BC membranes for protecting wounds from Pseudomonas aeruginosa infection were investigated. The AlgL was immobilised on never dried BC pellicles via physical adsorption. The maximum adsorption capacity of AlgL was 6.0 mg/g of dry BC, and the equilibrium was reached after 2 h. The adsorption kinetics was studied, and it has been proven that the adsorption was consistent with Langmuir isotherm. In addition, the impact of enzyme immobilisation on bacterial biofilm stability and the effect of simultaneous immobilisation of AlgL and gentamicin on the viability of bacterial cells was investigated. The obtained results showed that the AlgL immobilisation significantly reduced the amount of polysaccharides component of the P. aeruginosa biofilm. Moreover, the biofilm disruption by AlgL immobilised on BC membranes exhibited synergism with the gentamicin, resulting in 86.5% more dead P. aeruginosa PAO-1 cells.

The Simple Method of Preparation of Highly Carboxylated Bacterial Cellulose with Ni- and Mg-Ferrite-Based Versatile Magnetic Carrier for Enzyme Immobilization.

The bacterial cellulose (BC) is a versatile biopolymer of microbial origin characterized by high purity and unusual water and material properties. However, the native BC contains a low number of functional groups, which significantly limits its further application. The main goal of its effective modification is to use methods that allow the unusual properties of BC to be retained and the desired functional group to be efficiently introduced. In the present study, the new magnetic carrier based on functionalized citric acid (CA) bacterial cellulose was developed and tested to support critical industrial enzymes such as lipase B from Candida antarctica and phospholipase A from Aspergillus oryzae. The applied method allowed BC to be effectively modified by citric acid and a sufficient number of carboxylic groups to be introduced, up to 3.6 mmol of COOH per gram of dry mass of the prepared carrier. The DSC and TGA analyses revealed carrier stability at operational temperatures in the range of 20 °C to 100 °C and substantially influenced the amount of the introduced carboxyl groups on carrier properties. Both enzymes' immobilization significantly improves their thermal stability at 60 °C without a significant thermal and pH optima effect. The analyzed enzymes showed good operational stability with a significant residual activity after ten cycles of repeated uses. The new magnetic carrier based on highly carboxylated bacterial cellulose has a high application capability as matrix for immobilization the various enzymes of industrial interest.