Sustainable production of bacterial cellulose from delignified rice straw using Novacetimonas hansenii TGA isolate: Process optimization and membrane characterization.

The current study investigated the effect of different pretreatment approaches in the delignification of rice straw (RS) for sustainable bacterial cellulose (BC) production. Among the three pretreatment methods evaluated, acid/alkali pretreatment was the most effective (76.6 % delignification with increased α-cellulose and holocellulose to 90.1 % and 89.6 %, respectively) compared to hydrothermal and acid pretreatments (10.2 % and 30 % delignification, respectively). Enzymatic hydrolysis of acid/alkali-treated RS demonstrated maximum glucose liberation (17.4 mg/mL) using 25 % treated RS and 3 % cellulase cultivated at 42 °C and pH 5.7. A newly isolated and identified BC-producing strain, Novacetimonas hansenii TGA (GenBank: PQ610429), effectively converted RS hydrolysate into BC, with yield increasing to 3.21 g/L through supplementation with NaHPO and citric acid. Structural characterization revealed that BC from standard HS medium exhibited a dense nanofiber network (56 nm diameter, 82.4 % crystallinity), while modified media (R2, R4) produced thicker fibers (85-119 nm) with slightly reduced crystallinity (74.6-76.1 %). FT-IR confirmed characteristic cellulose bonds (OH, COC), with HS and R2 media yielding the most stable structures. These findings highlight the novel integration of efficient pretreatment, enzymatic saccharification, and optimized fermentation for cost-effective BC production from RS, supporting its potential in biomaterials, packaging, and medical applications.