Structural engineering of bacterial cellulose-deacetylated konjac glucomannan composite hydrogels via one step...

Bacterial cellulose (BC) is a high-purity, biodegradable polysaccharide commercialized in foods and promising for biomaterials. Yet BC composites face challenges achieving high yields with mechanical strength and thermal stability. Here, we move beyond "add-a-polysaccharide" approaches by leveraging konjac glucomannan (KGM) acetylation as a design parameter coupling fermentation operability with BC-polysaccharide interfacial co-assembly. Partially deacetylated KGM (DKGM, deacetylation degree 30.37%) was prepared to reduce viscosity and incorporated into BC via one-step in situ fermentation, while physical-mixture controls (BC-KGM-M and BC-DKGM-M) distinguished simple mixing from co-deposition. Under identical conditions, DKGM alleviated viscosity limitations and increased BC yield by 16.9% vs KGM, whereas native KGM showed no gain. FT-IR deconvolution and solid-state NMR revealed strengthened hydrogen bonding via deacetylation and more intimate associations in in situ composites than in mixture controls, while XRD confirmed retention of the cellulose Iα crystalline form. As a result, BC-DKGM exhibited a more compact architecture, enhanced tensile strength (0.37 MPa; ∼236.36% over BC) and thermal stability, superior viscoelasticity and recovery upon thermal cycling/creep, and a more immobilized water population. These findings demonstrate that tuning KGM acetylation enables predictable process-structure-property control in BC-based composite hydrogels via one-step strategy, expanding BC's applications in food and biomedical fields.