Enzymatic Isolation of Erucic Acid from HEA Oils, with Biodiesel as A By-Product: Preliminary Investigation

Abstract

Erucic acid (EA) is a fatty acid with wide industrial applications. Currently, EA is isolated from higherucic acid (HEA) Crucifereae plant oils by steam splitting, namely Colgate-Emery process, followed byfractional distillation. Some disadvantages are caused by the drastic conditions used in this two-step process.Meanwhile, another product from vegetable oils, biodiesel, is not so widely used as it should be in the UnitedStates because of its high production cost.<br><br>EA and biodiesel could be simultaneously produced through enzymatic processes in mild conditions. Differentreaction routes were investigated in this study to isolate EA from HEA plant oils using different lipases withdifferent specificities. Specifically, the hydrolysis of crambe oil catalyzed by lipases from Candida rugosa andporcine pancreas were investigated and compared. Porcine pancreatic lipase (PPL) preferentially liberated EAlocated at the two primary positions of oil triacylglycerols (TAGs). The EA content in free fatty acid fractionreached 82.2%, with an EA recovery of 71.7%. By contrast, Candida rugosa lipase (CRL) preferentiallyreleased short-chain FAs from oil TAGs, and left long-chain EA behind on the glycerol backbone as a productof sn-1, 3-dierucin. To reduce the considerable loss of EA into free fatty acid fraction, sn-1, 3-dierucin neededto be separated during the CRL hydrolysis process.<br><br>Preferences were initially given to the alcoholysis and interesterification catalyzed by lipase from Candidarugosa in attempt to combine EA isolation and biodiesel production in a single-step reaction. However, nofeasible results were achieved successfully due to the adverse effects of the acyl acceptors, namely alcoholsand esters, for those two reactions.