Valorization of starch waste-derived glucose for bacterial cellulose production: Feedstock optimization and material characterization

The increase of starch-rich waste from the food industry presents both environmental challenges and opportunities for value-added bioprocessing. This work investigates the potential use of starch scrap waste from food industry as a cost-effective and sustainable feedstock for bacterial cellulose (BC) production. Tapioca starch waste was hydrolyzed into glucose using enzymatic treatment, and the process was optimized by response surface methodology. The optimal condition of 2.78% (w/w) α-amylase and 1.21% (w/w) glucoamylase yielded an experimentally validated glucose content of 301.682 ± 0.327 g/L and a conversion yield of 90.59 ± 0.098%. The obtained hydrolysate was employed as the primary carbon source for Komagataeibacter nataicola cultivation in order to produce BC. Hydrolyzed glucose (HG) produced approximately 2.9–3.0 g/L BC after 7 days, with a higher production yield of 15%, compared with standard glucose (SG). Physicochemical characterization showed that HG-BC retained the characteristic cellulose structure and nanofibrillar morphology, with a fibril diameter of 33.51 ± 5.21 nm, bulk porosity of 82.36 ± 3.92%, and crystallinity index of 90.8 ± 0.72%. HG-BC also exhibited a higher thermal degradation peak (358.9 °C) than SG-BC (317.1 °C). These findings demonstrate that starch scrap waste can be efficiently converted into a glucose-rich feedstock for enhanced BC production while yielding structurally ordered and thermally stable cellulose, supporting waste valorization and circular bioeconomy-based materials for food and related applications.