Mato Grosso Probes Corn Ethanol Plants for Illegal Deforestation

As of November 1st, 2025, prosecutors in the Brazilian state of Mato Grosso are investigating whether corn ethanol plants in the region are illegally burning wood from deforestation to produce biofuel. Mato Grosso is Brazil's top soybean producer and accounts for two-thirds of the country's corn ethanol output, which has surged in recent years.

The investigation seeks to determine if some plants are burning native wood, which is significantly cheaper than using planted trees, to generate energy for the production process. This would run counter to the industry's goal of reducing its carbon footprint through the use of renewable fuels.

According to the Mato Grosso Reforesters Association, more than 50% of the wood consumed by the corn ethanol sector currently comes from the felling of native trees, rather than from planted forests. This shortage of sustainable biomass is a growing concern, as the state would need 30,000 hectares of eucalyptus plantations to fuel its projected corn ethanol production by 2025/26.

If the allegations are confirmed, prosecutors say they will recommend revoking a 2022 state rule that allows the use of native biomass in industry, citing the difficulty of tracking the origin of wood burned in production. The investigation highlights the challenges Brazil faces in balancing its biofuel ambitions with the need to curb deforestation, a major source of the country's greenhouse gas emissions.