The Reuseable Enzymatic Biodiesel Unit (REBU) will be a device that can be placed in or attached to a small-scale biodiesel reactor. This device will incorporate immobilized lipase enzymes to allow the expensive enzymes to be reused. Ideally our final solution can be incorporated into an existing reactor. Most small-scale reactors we are familiar with use a stirring motor to mix the reactants. With that in mind, some early ideas for the REBU include stirrer blades with imbedded enzymes or a device that looks like a wiffle ball that can be thrown into the reactor vessel. An alternative solution that has been discussed is some sort of tube or canister with immobilized enzymes. The biodiesel reactants would be pumped through the tube and react with the enzymes in the tube. One student proposed such a device based on a swimming pool cleaning system.
Either type of solution to this problem would have to meet certain criteria. First, the enzymes would have to be reusable. Our initial goal is to have a product that can be used to produce 1,000 gallons of biodiesel before the enzymes have to be replaced. The entire device would have to be low-cost. Our current target is to produce a device that costs under $300. This cost is based on the canister solution which would have to incorporate a diesel transfer pump. The device would have to produce biodiesel with a 95% yield. Finally, replacing enzymes in the device would have to be an easy process since the device will be used by small-scale producers who might have very little knowledge of the chemistry of the production process.