Comparative Biomaterial Analysis of Cellulose Produced by Caffeinated and Decaffeinated Kombucha Symbiotic Cultures of Bacteria and Yeast (SCOBY)

Bacterial cellulose produced by kombucha symbiotic cultures of bacteria and yeast (SCOBY) is an emerging biomaterial with potential applications in food packaging and biomedical engineering. For example, recent studies have investigated integration of SCOBY-produced cellulose into tissue grafts. Meanwhile, given regulations on restaurants, grocers and the gradual phasing out of plastic in areas such as California, finding biodegradable materials with sufficient tensile strength is not optional. Replacing plastic with unsuitable materials may lead to food waste if the contents are not genuinely contained by the vessel, or do not serve their intended function. This pilot study investigated how caffeinated and decaffeinated black tea influence fermentation, cellulose production, and properties. We hypothesized differences in tea composition would alter microbial activity and cellulose biosynthesis, resulting in differences in pellicle growth, structure, and mechanical performance. Identical fermentation systems were established under controlled conditions, and pH, pellicle thickness, biomass, moisture content, tensile strength, water rehydration, putative Gram staining, and scanning electron microscopy (SEM) were used to characterize the resulting bacterial cellulose.

The decaffeinated treatment exhibited greater fermentation activity, producing a larger decrease in pH and thicker cellulose pellicles at 1.4mm compared with 0.8mm in the caffeinated treatment. The decaffeinated cellulose demonstrated greater tensile strength (9,032 psi; 4,608 psi) and lower moisture content (95.6% versus 97.5%), indicating a denser cellulose network. Rehydration experiments showed lower water uptake in decaffeinated pellicles (275%) than caffeinated pellicles (325%). SEM analysis at 3500× magnification revealed more compact, less porous cellulose architecture in the decaffeinated treatment, while caffeinated samples exhibited greater porosity and less organized fiber structure. Gram staining identified mixed communities that included putative Gram-negative bacteria, consistent with acetic acid bacteria, together with yeast populations identified by morphology.

These findings demonstrate that tea composition influences bacterial cellulose production and biomaterial properties. Decaffeinated tea promoted stronger, thicker, and more structurally organized cellulose, supporting its potential as a renewable biomaterial for sustainable food-related and biodegradable applications. Further studies must confirm these results with bacterial and fungal identification that relies on morphology as well as additional evidence such as sequencing data.  Replication must be implemented to allow for statistical analysis.