Valorization of agro-industrial wastes for low-cost production of bacterial nanocellulose by Rhizobium leguminosarum biovar trifolii

To date, the production of bacterial nanocellulose (BNC) using commercial culture media has been well studied. In contrast, the use of low-cost feedstocks as alternative carbon sources remains to be explored. BNC is highly valued worldwide due to its physical, chemical, and mechanical properties. In this study, we investigated BNC production by Rhizobium leguminosaurium biovar trifolii using culture media modified with different agro-industrial wastes, such as pineapple (P), banana (B), and orange (O) peels. For BNC production, we tested various treatments using a yeast-lactose (YL) culture medium as a control, YL medium supplemented with 5 %, 10 %, and 20 % extract from agro-industrial wastes, and a lactose-free (LF) YL medium with 5 % extract. The treatments were incubated in the dark at 28 °C for 15 days. The yield and physicochemical properties of the BNC were analyzed using Fourier-transform infrared spectroscopy (FTIR), zeta potential, transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). The highest yield was observed in the P5 %-LF treatment, followed by the B5 % and P5 % treatments. TEM images revealed BNC with a fibrillar morphology, measuring between 30 nm and 50 nm, and FTIR spectra displayed characteristic cellulose peaks. The BNC had a negative charge, ranging from −21.8 to −72.2 mV, indicating that the BNC suspension remains stable in water. This study highlights the potential of using extracts from pineapple, banana, and orange peels as alternative nutrient sources for preparing culture media aimed at low-cost BNC production. • Rhizobium leguminosarum produces BNC using fruit peel extracts. • Pineapple and banana peels boost yield up to 1.6 g/L (+201 % vs control). • BNC showed high colloidal stability (ζ-potential up to –74 mV). • TGA revealed enhanced char retention and thermal stability with extracts. • Cost analysis shows 85–95 % media savings vs. Hestrin–Schramm medium.