Fabrication of bacterial cellulose composites with antimicrobial properties by in situ modification utilizing the specific function-suspension containing water-insoluble magnolol

In situ modification is commonly employed for Bacterial cellulose (BC) functionalization. However, water-insoluble modifiers are usually deposited at the bottom of the medium, therefore cannot be used for in situ modification of BC. Herein, a novel strategy for in situ modification of insoluble modifiers after suspension by a suspending agent was proposed. The BC-producing strain Kosakonia oryzendophytica FY-07, not Gluconacetobacter xylinus, was selected to prepare BC products with antibacterial activity because of its tolerance to natural antibacterial products. The experimental results showed that xanthan gum as a suspending agent can uniformly and stably disperse water-insoluble plant extracts magnolol in the culture medium to prepare the in situ modified BC products. Characterization of the properties showed that the in situ modified BC products have reduced crystallinity, significantly increased swelling ratio and strong inhibition on Gram-positive bacteria and fungi and weak inhibition on Gram-negative bacteria. Furthermore, the in situ modified BC products had no toxicity to cells. This study provided a feasible strategy for in situ modification of BC using water-insoluble modifiers to extend BC functionality and has significant implications for the biopolymer industry.