LCA studies comparing alkaline and immobilized enzyme catalyst processes for biodiesel production under Brazilian conditions

Brazil is a leader in the production of biodiesel, and some challenges still exist in improving the energy usage and feedstocks alternatives for the transesterification process. In this paper, an industrial scale simulation was conducted to show a comparison of the traditional alkali-catalyzed process using catalysis sodium hydroxide with an enzyme-catalyzed process novel developed by the research team of one of the authors. LCA methodology was used to evaluate the potential multiple effects on the environment in Brazilian scenarios. In this regard, three basic cases were carried out: Case 1, where 1t of soybean biodiesel was produced from the alkali-catalyzed process; Case 2 and 3, where 1t of biodiesel, using the enzyme-catalyzed process, was produced from soybean oil and waste cooking oil respectively. The results reveal that considerable contribution can be made to the environment in Case 3 when waste cooking oil (WCO) is considered as a nearly environment-burden-free resource. Additionally, as illustrated in Case 2, not only the feedstock but also the technologic process can generate great influence on the environment when producing biodiesel in a large-scale plant. The efficiency of electric and thermal energy usage should be appropriately considered to diminish these impacts as much as possible. Likewise, chemicals and waste disposal also need to be well managed.