From Grave to Cradle: Kombucha Waste for Sustainable Electronics

The increasing reliance on petroleum-based polymers in electronics contributes significantly to electronic waste. Kombucha bacterial cellulose (KBC), a renewable and compostable byproduct of kombucha fermentation, presents an eco-friendly alternative. However, the absence of sustainable fabrication methods for high-performance KBC films has limited their electronic applications. This study introduces an environmentally benign process for pulping, purifying, and forming KBC sheets optimized for sustainable electronics. Treatment with sodium bicarbonate and hydrogen peroxide yields a sterile, white KBC film with enhanced properties. Comprehensive characterization via TGA, XRD, and FTIR confirms the material's high purity and crystallinity while preserving its native chemical structure. Mechanical testing demonstrates that processed KBC films exhibit superior tensile strength compared to untreated samples. Additionally, a gold-sputtering technique is established to create conductive circuits on KBC substrates, achieving stable electrical conductivity even under mechanical stress. As a proof of concept, this platform, in a functional pressure sensor for flatfoot assessment, is successfully implemented. A key advantage of KBC is its rapid biodegradation, completing the material lifecycle within days. These results position KBC as a promising, sustainable biomaterial for next-generation green electronics.