Methyl ester soybean oil, also known as biodiesel, is a renewable fuel made from soybean oil through a process called transesterification. In this process, soybean oil is reacted with an alcohol (usually methanol) in the presence of a catalyst to produce methyl esters (biodiesel) and glycerin.

Methyl ester soybean oil can be used as a diesel fuel alternative, either on its own or blended with petroleum diesel, to reduce greenhouse gas emissions and dependence on fossil fuels.