# From Grave to Cradle: Kombucha Waste for Sustainable Electronics

## TL;DR

This paper presents a sustainable method to create electronic devices using kombucha waste, which can biodegrade after use, reducing electronic waste.

## Contribution

The study introduces a chemical-free purification process for KBC and demonstrates its use in biodegradable electronic devices.

## Key findings

- Processed KBC films show superior tensile strength and high purity compared to untreated samples.
- Gold-sputtered KBC substrates achieve stable electrical conductivity under mechanical stress.
- KBC-based devices biodegrade in soil, leaving only recoverable gold residues.

## Abstract

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.

This study introduces a sustainable method to purify kombucha bacterial cellulose (KBC) with sodium bicarbonate and hydrogen peroxide, avoiding harsh chemicals. KBC films are patterned with gold and function as pressure sensors for flatfoot gait detection. At the end‐of‐life, the KBC‐based device biodegrades in soil, leaving environmentally benign gold residues, while other electrical components are recovered for reuse, ensuring sustainability.