Sustainable Bacterial Cellulose Production from Avocado Seed Waste Using a Green Biorefinery Approach

In this study, avocado seed (AS) waste was used as a feedstock for bacterial cellulose (BC) production. Global avocado consumption continues to rise due to its recognised health benefits, resulting in substantial amounts of waste generated by the avocado processing industry. This work proposes the efficient utilisation of avocado seed residues—rich in fermentable sugars—to enhance the economic viability of BC production while supporting responsible agro-industrial waste management. Hydrolysed avocado seeds were incorporated into a modified Hestrin–Schramm (MHS) medium for BC production using Komagataeibacter xylinus as the bacterial strain. The BC membranes obtained from the modified medium (BC-MHS) exhibited higher production (1.93 g/L) and productivity (0.19 g/L·day) compared with those produced in the standard HS medium (BC-HS). The morphology and nanofibre diameter (11–85 nm) of the resulting BC were not significantly affected; however, BC-MHS showed higher crystallinity (~78%) and a higher degradation temperature (~357 °C) than BC-HS. Conversely, the modified medium slightly reduced the mechanical performance of the BC in terms of elongation at break, tensile strength, and Young’s modulus. Overall, avocado seed waste was successfully transformed into a value-added material, demonstrating its potential for agro-industrial waste valorisation through scalable and sustainable biorefinery processes.