Novel Enzyme-catalyzed Process for Continuous Commercial Scale Biodiesel Production

In biodiesel production, plant oils are usually reacted with an alcohol (commonly,methanol) to produce a mixture of compounds known as methyl esters (the "biodiesel" product). The reaction (which is called "transesterification") is usually catalyzed by a base, such as sodium hydroxide. Because base-catalysts can reduce the biodiesel yield due to side-reactions, scientists are exploring alternative catalyst-materials.

Alternative catalysts for the transesterification reaction in biofuel production are enzymes, such as those that belong to the family of lipases (triglyceride hydrolases). Lipases are said to be efficient and selective for the transesterification reaction. However, the cost and possible instability make enzymes unfavorable for industrial biodiesel production applications.

A team of French researchers from French National Center for Scientific Research (CNRS), the Institute for Molecular Sciences (France) and the Laboratory of Condensed Matter Chemistry (France) report a way to overcome the above-mentioned problems. They employed monolithic biohybrid foams to confine the enzymes for a relatively long period of time (approximately 2 months). Confinement in the biohybrid foams allowed good accessibility and enhanced mass transport, resulting in a high biodiesel yield. The long term stability of the enzymes make the process attractive for commercial applications. The researchers then devised a method for the in-situ production of the new biocatalyst in the reactor itself; thus, allowing uninterrupted, continuous, unidirectional flow industrial production of this biofuel. The biodiesel yields from this novel method were the best achieved so far and it met all the current energy and environmental requirements and standards. According to the researchers, the next step in the research is the solvent-free conversion of triesters, aimed at minimizing waste production by curbing the use of solvent sand metals in chemical transformation processes. The full study is published in the journal, Energy and Environmental Science (URL above).