Feasibility assessment of waste banana peduncle as feedstock for biofuel production

Tropical and sub-tropical countries grow bananas in large quantities. About 13% by weight of the harvested banana cluster is banana peduncle waste, usually discarded or composted. The feasibility of using this waste as a feedstock to produce biofuels like ethanol and biogas was evaluated. Commercially available equipment was used to crush the peduncle, resulting in 0.591 g of juice/g fresh peduncle composed of glucose (7  g/L), sucrose (3  g/L) and fructose (8  g/L). Five-day fermentation of five times concentrated peduncle extract yielded 0.41 g ethanol/g sugars, without need for any additional nutrient for fermentation; higher concentrations were inhibitory. Additionally, the residual bagasse after extraction and stillage (after ethanol distillation), was successfully anaerobically digested to produce biogas. The methane yields were 0.263 L methane at standard temperature and pressure (STP)/g volatile solids (VS) of bagasse, and 0.08 L methane at STP/g VS stillage which resolves approximately 68% of energy requirements for the concentration step. In Ecuador, about 4 million liters of ethanol can be produced from peduncle. It is envisaged that the concentrated syrup can be prepared at the packing house using biogas from peduncle bagasse as fuel, then dispatched to an ethanol-processing central facility.