Lettinga Award

The Lettinga Award 2026 was awarded to the project “Closing potassium cycles in banana production through anaerobic biorefinery systems” submitted by Adrián Enrique Quinto Carrillo from the Institute of Renewable Energy of UNAM, Mexico. The judges applaud the focus on the use of an underutilized substrate, addresses potassium as an important limiting resource and closes nutrient cycles locally.

The winning project aims to valorise banana pseudostem residues through a decentralized separation and biorefinery system based on anaerobic processes. On banana plantations large volumes of lignocellulosic residues remain after harvesting and these are currently underutilized despite their high potassium content. As banana cultivation requires significant potassium input there exists an opportunity to locally close this nutrient cycle.

In the project pseudostems are processed yielding a liquid fraction rich in soluble nutrients and a solid fibrous fraction. The liquid is anaerobically fermented to produce a stabilized potassium-rich liquid fertilizer. The solid fraction is digested to generate biogas as a renewable energy source as well as a nutrient rich digestate, which is useful as a soil amendment.

The proposed treatment of the residues is currently at an early conceptual stage (TRL1-2) and with the funding the project aims to establish a proof-of-principle for an integrated and scalable solution, which supports sustainable agriculture, renewable energy generation and circular resource management.