One-step enzymatic production of fatty acid ethyl ester from high-acidity waste feedstocks in solvent-free media

► An enzymatic biodiesel production from high-acidity waste feedstocks is demonstrated. ► Said production is carried out in a single pass and with no addition of co-solvents. ► Said production involves simultaneous esterification and transesterification reactions. ► An empirical equation was derived to determine the kinetics of said production. ► Using said equation one can predict the rate of FAEE production from other feedstocks.