Simultaneous extraction and separation of phorbol esters and bio-oil from Jatropha biomass using ionic liquid–methanol co-solvents

Abstract

This work evaluates the applicability of an ionic liquid–methanol co-solvent system to extract phorbol esters from jatropha biomass. The extracted phorbol esters readily solubilized into the co-solvent due to a shared amphiphilic nature. Methyl sulfate anion had superior performance relative to acetate anion, extracting and solubilizing higher quantities of phorbol esters. Compared to traditional methods which only extract phorbol esters, the co-solvent system simultaneously extracted and separated the bio-oil to its own separate immiscible phase and with no appreciable loss of protein – the majority of protein remaining with the biomass and only a small residual amount (∼1mg/ml) solubilizing into the co-solvent. The optimum co-solvent concentration for simultaneous extraction of phorbol esters and bio-oil was determined to be 30wt% IL and 70wt% methanol. With respect to the extracted kernel biomass, the high proportion of protein (68–70%) and low phorbol esters (0.15mg/gkernel) content suggested a high suitability as an animal feed.