High-yield bacterial cellulose production from rice bran using a genetically characterized Komagataeibacter europaeus strain

A high-yielding Komagataeibacter europaeus strain, KFET1, was evaluated for its capacity to utilize rice bran as a cost-effective substrate for bacterial cellulose (BC) production. By employing an optimized enzymatic hydrolysis approach, the yield of rice bran-derived BC (RB-BC) reached 15.67 g/L, a 389.06 % improvement over Hestrin-Schramm-derived BC (HS-BC). RB-BC demonstrated superior nanofiber uniformity, rehydration capacity, and thermal stability, confirmed by FTIR, SEM, DSC, X-ray diffraction, and solid-state NMR analyses. Scale-up fermentation in a 15 L bioreactor achieved a BC yield of 20.69 g/L and a sugar conversion rate of 87.85 %. The high BC yield (20.69 g/L) stems from synergistic interactions between the KFET1 strain's enhanced carbohydrate metabolism (264 genes) and enzymatic hydrolysis-driven nutrient release from rice bran. Economic analysis demonstrated a profit of 1166.42 USD/ton for rice bran medium, significantly exceeding values for Hestrin-Schramm (-153.06 USD/ton) and coconut water (906.33 USD/ton), highlighting rice bran's cost-effectiveness. This study provides an efficient and sustainable strategy for converting agricultural by-products into high-value biomaterials, paving the way for industrial-scale BC production.