Production of Bacterial Cellulose Hydrogel and its Evaluation as a Proton Exchange Membrane

Production of bacterial cellulose hydrogel and its evaluation as a proton exchange membrane (PEM) was evaluated. Initially, the bacterial cellulose hydrogel membranes (BCH) was produced by fermentation in a 600 mL bioreactor with a 300 mL medium volume, 10% v/v inoculum with Komagataeibacter hansenii under static conditions, and a temperature of 30 °C. The bacteria were cultivated in Hestrin-Schramm (HS) medium with pH adjustment to 6.6 with HCl and/or NaOH. Five culture media were evaluated to obtain uniformity on the surface and a rapid formation of BCH membrane: HS (M1), M1 + green tea extract (M3), M1 + mixture of extra thyme and green tea (M4), and M1 + glycerin (M5). The kinetics of BCH production was followed by digital images. Subsequently, BCH production cellulose was carried out using M5 under the same operating conditions. After 3, 5, 10 and 13 days of fermentation, the thickness of BCH formed was measured, respectively, as 0.301 ± 0.008 cm, 0.552 ± 0.026 cm, 0.584 ± 0.03 cm and 0.591 ± 0.018 cm. Finally, BCH was characterized by porosity, water absorption capacity, ion exchange capacity, mechanical strength and diffusivity. The results showed that thinner membranes favor the processes of ion exchange (0.143 H⁺mmol g⁻¹) and water absorption (93%). On the other hand, thicker membranes enhance physical parameters of transport across the membrane and its operability. Nevertheless, BCH membranes can be a good alternative as PEM to microbial fuel cell once they are functionalized.