Optimization of Bacterial Nanocellulose Production from Sweet Potato Waste via Response Surface Methodology

Cilembu sweet potato is a high-yielding Indonesian variety that generates considerable agro-industrial waste from unconsumed biomass.Owing to its high carbohydrate content, this waste hydrolysate was evaluated as a carbon source for the cultivation of Gluconacetobacter xylinus to produce bacterial nanocellulose (BNC).Production parameters were optimized using a Box-Behnken experimental design to assess the effects of initial pH, bacterial inoculum volume, and D-glucose concentration on BNC yield.Statistical analysis indicated that both pH and inoculum concentration significantly influenced yield, whereas D-glucose concentration had no statistically significant effect (p = 0.059).Optimal conditions were identified at pH 5.7 and 10% inoculum, yielding 3.97 g/L of BNC.The synthesized BNC consisted of interconnected nanofibers of 10-100 nm in diameter, with a crystallinity index of up to 77%.Collectively, these results demonstrate that Cilembu sweet potato waste hydrolysate represents an efficient and sustainable carbon substrate for BNC biosynthesis, eliminating the need for additional glucose supplementation.