Oil extraction from Jatropha curcas seeds by enzymatic extracts from Bromelia pinguin

Abstract

To develop a method for the enzymatic extraction of oil from the meal of the bioenergy plant Jatropha curcas (Euphorbiaceae), the study evaluated extracts from the tropical plant Bromelia pinguin (Bromeliaceae), which exhibits protease activity as well as the operating conditions (enzyme concentration, reaction temperature, initial mixture pH, and agitation speed) that maximize oil extraction efficiency. It was determined that stem and leaf extracts lacked proteolytic activity, whereas aqueous fruit extracts showed an activity of 2.1 ± 0.26 µkat mL^-1 and the partially purified protein showed 13.9 ± 0.95 µkat g^-1. Oil extraction efficiency from J. curcas meal was highest under the following operating parameters: 18 or 20 U g^-1 of meal, temperatures between 30 ºC and 45 ºC, an agitation speed of 50 rpm, and pH levels of 4.0 and 6.0. The physicochemical characteristics of the enzymatically extracted J. curcas oil were like those of hexane-extracted oil, except for statistically higher values regarding the acid value and melting point. Oil extraction efficiency from J. curcas using B. pinguin proteases ranged from 31.1 % to 32.1 % relative to extraction via the Soxhlet method using hexane as the solvent.