Enzymatic synthesis of estolides by a bioreactor

An attempt was made to synthesize ricinoleic acid estolides effectively with a bioreactor system containing immobilized lipase. The optimal water content for reaction changed during synthesis of estolide from ricinoleic acid. The water content needs to be controlled to optimize conditions for each reaction stage and to prepare estolide with a high degree of condensation. The estolide synthesis was attempted to confirm if the reaction would have proceeded to the targeted degree of condensation by controlling the reaction mixture under the optimal water content. The result showed that, with the bioreactor, the reaction could proceed rapidly. A repeated batch reaction was possible in the bioreactor. The amount of lipase used can thus be highly reduced compared with discarding it each time. The loading density of enzyme onto the carrier greatly affected enzymatic activity, with a loading level of 60 mg lipase/g carrier producing 60% more estolide per gram of enzyme than a loading level of 120 mg/g. The estolide product synthesized in the bioreactor showed no coloration during the reaction process. This fact confirmed the validity of the proposed method.