Microbial extracellular polysaccharide-based membrane in polymer electrolyte fuel cells

• Extraction of polysaccharide from Rhizobium for the fabrication of membrane.
• Exopolysaccharide (EPS) membrane cross-linked with SSA for proton conductivity.
• EPS-based membrane electrode assembly for polymer electrolyte fuel cells.

The extracellular polysaccharides (EPS) produced by a bacterium, Rhizobium sp. MBJ1 (Accession No. JF713722) isolated from the stem nodules of Aeschynomene indica (L) was precipitated using acetone and characterized for its viscosity and composition of sugar. A cross-linked polymer electrolyte membrane was prepared by blending EPS and sulfosuccinic acid (SSA). SEM morphology showed the presence of SSA in the EPS matrix. Water sorption, ion-exchange capacity (IEC), thermogravimetric analysis (TGA) and proton conductivity properties for the membrane were investigated. The fabricated membrane electrode assembly comprising the EPS membrane showed a peak power density of 400 mW cm−2 at a load current density of 1250 mA cm−2 in polymer electrolyte fuel cells (PEFCs).