Bacterial cellulose, the pure nanofibrillar polymer secreted by certain acetic acid bacteria, has long been prized for biomedical scaffolding, but its lack of intrinsic antimicrobial activity and limited flexibility have kept it out of many clinical settings.
The work centered on a strain called Komagataeibacter saccharivorans APPK1, which the authors had previously optimized to produce bacterial cellulose films using pineapple peel waste as the growth medium. After fermentation, the gel-like pellicles were purified in sodium hydroxide at 70 degrees Celsius and washed until colorless, yielding hydrated membranes that served as the base material for all subsequent composites. From this starting point, the team fabricated six composites, labeled BCC-01 through BCC-06, each with a distinct recipe drawn from a short list of functional additives: gelatin, chitosan, sodium alginate, calcium chloride, polyethylene glycol, acetic acid and glutaraldehyde.
The formulations differed in ways that proved consequential. BCC-01 combined bacterial cellulose slurry with 2 percent sodium alginate and 15 percent gelatin in a 60:20:20 ratio, crosslinked with 1 percent calcium chloride. BCC-02 added 2 percent chitosan and 10 percent gelatin alongside alginate. BCC-03 paired cellulose with alginate alone, while BCC-04 mixed cellulose with 2 percent chitosan dissolved in 1 percent acetic acid and crosslinked the blend with 2 percent glutaraldehyde. BCC-05 was grown in gelatin-enriched medium and crosslinked with 10 percent glutaraldehyde, and BCC-06 was partially dehydrated, soaked in 1 percent polyethylene glycol for two hours and freeze-dried. Each composite was then subjected to a battery of characterization techniques: Fourier-transform infrared spectroscopy, powder X-ray diffraction, field emission scanning electron microscopy, thermogravimetric analysis, water absorption testing, disk diffusion antimicrobial assays and an MTT-based cell viability test.
The spectroscopic results pointed to extensive intermolecular hydrogen bonding between cellulose and every additive. Pure bacterial cellulose showed its characteristic hydroxyl stretching band at 3281 per centimeter, but each composite shifted that band downward, to values between 3201 and 3228 per centimeter depending on the formulation. In BCC-06, the shifts reflected hydrogen bonds forming between the hydroxyl groups of cellulose and the ether-linked chemistry of polyethylene glycol. In BCC-04, the authors attributed the altered bands to interactions between cellulose hydroxyls and the hydroxyl and amino groups of chitosan, with additional bonding to the carbonyl groups of glutaraldehyde and the acidic group of acetic acid. These hydrogen bond networks, the study argues, are what give the composites their improved stability and mechanical character.
X-ray diffraction told a parallel story about crystallinity. Pure bacterial cellulose I displays sharp diffraction peaks at 22.7, 26.6, 31.7 and 45.3 degrees two-theta, but every composite lost much of that ordered signature. BCC-06 showed only a broad, low-intensity peak near 22 degrees, which the authors interpret as substantial suppression of crystalline domains caused by polyethylene glycol disrupting the native intramolecular network. BCC-04, crosslinked with glutaraldehyde, showed a similarly attenuated peak, and the paper concludes that chemical crosslinking drives more pronounced amorphization than simple polymer blending. BCC-03 retained the clearest, though weakened, fingerprints of cellulose I. The practical implication of this crystalline-to-amorphous transition, according to the authors, is improved flexibility and adaptability of the films.
Electron microscopy revealed how dramatically the additives reshaped surface architecture. Pure bacterial cellulose shows an open fibrous network with high porosity, but the composites progressively closed that structure down. BCC-04 was the densest material of all, with merged fibrils and almost no visible pores, a morphology credited to strong interactions and crosslinking among cellulose, chitosan, acetic acid and glutaraldehyde. BCC-06, by contrast, displayed a smoother, more continuous surface with partially merged fibers, consistent with polyethylene glycol filling the spaces between fibrils. BCC-01 retained a fibrous arrangement with visible calcium chloride particles, apparently strengthened by ionic crosslinking, while BCC-03 showed a smooth surface and reduced porosity from the alginate and calcium chloride combination.
Water absorption varied enormously across the panel. Pure bacterial cellulose absorbed 373.25 plus or minus 2.4 percent of its dry weight. BCC-06 far exceeded that benchmark at 476.5 plus or minus 5.6 percent, which the authors attribute to the hydrophilic ether oxygen groups of polyethylene glycol binding water molecules. BCC-01 came second at 434 plus or minus 4.5 percent, helped by alginate and gelatin. At the opposite extreme, BCC-04 absorbed only 135 plus or minus 2.8 percent, the lowest of all, apparently because its dense crosslinked network limits water penetration. BCC-02, BCC-03 and BCC-05 fell in between at 299, 286.5 and 374.5 percent respectively, demonstrating that composition, not cellulose alone, dictates hydration behavior.
Thermal analysis added another dimension of differentiation. Pure bacterial cellulose degrades in three stages: moisture loss near 100 degrees Celsius, major decomposition between 130 and 350 degrees Celsius, and secondary breakdown extending to 600 degrees Celsius. Four composites, BCC-01 through BCC-04, retained 31 to 45 percent residual mass and outperformed pure cellulose thermally, an effect linked to the char-forming and reinforcing behavior of alginate, chitosan and the crosslinkers. BCC-03 was the most stable of all at 45 percent residue, reflecting stabilizing alginate-calcium interactions. BCC-05 and BCC-06 fared poorly, retaining only 5 to 6 percent residue because gelatin and polyethylene glycol degrade early. Notably, the abstract highlights BCC-04’s enhanced thermal stability, attributed to robust interactions among glutaraldehyde, chitosan and cellulose, even though BCC-03 held the single highest residue value.
The antimicrobial results were the most selective of the study. Tested by disk diffusion against six bacterial strains, Escherichia coli, Vibrio cholerae, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis and Enterococcus faecalis, only three composites showed any activity. BCC-02, containing chitosan and alginate, produced inhibition zones of 15 plus or minus 0.816 millimeters against E. faecalis, 13.5 plus or minus 1.08 millimeters against S. aureus, 14.1 plus or minus 0.29 millimeters against E. coli and 15.5 plus or minus 0.4 millimeters against V. cholerae, with a weaker 7.5 plus or minus 0.41 millimeter zone against P. aeruginosa. BCC-04 was broadly effective, with zones ranging from 12.8 plus or minus 0.1 millimeters against P. aeruginosa to 19 plus or minus 0.7 millimeters against E. faecalis. BCC-05 was the strongest performer overall, reaching 20.7 plus or minus 0.2 millimeters against E. faecalis and staying between 15.5 and 18.6 millimeters against every other strain. The remaining composites, BCC-01, BCC-03 and BCC-06, showed no inhibition, which the authors ascribe to the absence of antimicrobial agents such as chitosan and glutaraldehyde.
Biocompatibility testing on a human retinal pigment epithelial cell line, RPE1, rounded out the evaluation. With control cells set at 100 percent viability, composites BCC-04 and BCC-05 supported the highest relative proliferation, at 113.35 plus or minus 1.6 and 119.34 plus or minus 2.0 percent respectively, suggesting their surface characteristics actively promote cell adhesion and growth. BCC-01, BCC-06 and pure bacterial cellulose performed comparably to the control, while BCC-03 fell to 85 plus or minus 1.4 percent and BCC-02 dipped slightly to 88.8 plus or minus 1.69 percent, possibly due to surface or porosity constraints. Preliminary assessments across the panel confirmed the materials were non-toxic. Taken together, the authors conclude that BCC-04 and BCC-05, which combine strong antibacterial activity with excellent cell support, are the leading candidates for further in vivo testing and for applications such as antimicrobial wound dressings and tissue-engineering scaffolds, while the broader panel illustrates how deliberately chosen additives can tune bacterial cellulose across a wide functional range.
Subject of Research: Development and characterization of six bacterial cellulose composites with enhanced functional properties for biomedical applications
Article Title: Tailoring bacterial cellulose composites derived from Komagateibacter saccharivorans APPK1: functional enhancements for biomedical applications
Article References: Patel, A., Parmar, M., Patel, P., Patel, B., Pandya, A., Patel, R., & Gosai, H. (2026). Tailoring bacterial cellulose composites derived from Komagateibacter saccharivorans APPK1: functional enhancements for biomedical applications. Biotechnology for Sustainable Materials, 3(1), Article 2. https://doi.org/10.1186/s44316-025-00052-z
Image Credits: AI Generated
DOI: 10.1186/s44316-025-00052-z
Keywords: bacterial cellulose, Komagataeibacter saccharivorans, chitosan, biocomposites, antimicrobial activity, wound dressings, tissue engineering, polyethylene glycol, glutaraldehyde, biocompatibility, FTIR, thermogravimetric analysis
News Source: Denise Maddox. (October 29, 2026). Bacterial Cellulose Composites Engineered for Wound Dressings Show Antibacterial Power. Scienmag.
