Bacterial Cellulose Production by a Novel Levilactobacillus brevis Isolate Using Response Surface-Optimised Agro-Industrial Substrates

High culture medium costs economically constrain bacterial cellulose (BC) production. In parallel, agro-industrial wastes are plentiful but often underutilised sources of carbon and nitrogen substrates that could support microbial growth and metabolite production. This study aimed to bioconvert agro-industrial waste sustainably into BC using response surface methodology. A novel lactic acid bacterium, <i>Levilactobacillus brevis</i> DSS.01, isolated from nata de coco wastewater, was evaluated alongside <i>Acetobacter tropicalis</i> KBC and <i>Komagataeibacter xylinus</i> TISTR 086 for BC production using Australian agro-industrial wastes. Preliminary screening identified pear pomace and rice bran as optimal low-cost carbon and nitrogen sources, respectively. The response surface methodology employing Box-Behnken Design determined the optimal agro-industrial waste medium composition for <i>L. brevis</i> DSS.01 to produce BC at 1.56 ± 0.15 g/L. The optimised agro-industrial waste medium substituted 85% of standard Hestrin-Schramm medium components, suggesting a significant reduction in culture medium and production costs. Scanning electron microscopy revealed BC fibres from <i>L. brevis</i> DSS.01 maintained a uniform diameter. Fourier transform infrared spectroscopy and X-ray diffraction analyses indicated minimal structural deviation in BC produced from optimised agro-industrial waste medium versus standard medium. These findings demonstrate economic and sustainable BC production through valorisation of agro-industrial residues, establishing lactic acid bacteria as alternative BC producers with potential food-grade applications in circular economy frameworks.