Critical technological analysis for enzymatic biodiesel production: An appraisal and future directions

Biodiesel has attracted considerable interest in recent years as an alternative energy source, once the world petroleum and gas resources will soon be exhausted. Additionally, the biodiesel is a biodegradable and renewable fuel. The conventional alkaline process for biodiesel production generates undesirable by-products such as soaps, which make difficult biofuel separation and purification. This technology becomes less interesting in Brazilian industry, once the significant amount of raw material, available in Brazil, has as characteristic high acidity value. In this scenario, to find an alternative technology that could eliminate these problems is desired by Brazilian biodiesel market. Designed to overcome these drawbacks, the enzymatic biodiesel production has been studied due to some relevant advantages over conventional process, such as: glycerol can be easily recovered without any complex process, free fatty acids contained in the oils can be completely converted to esters and subsequent wastewater treatment is not required. Nevertheless, despite the advantages of using enzymatic biodiesel production, the enzymatic route is not an industrial-scale reality yet. There are some challenges that should be overcome before biocatalysts can be made feasible for biodiesel production, like their higher cost, biodiesel productivity, and enzyme inhibition.