Study On Aqueous Enzymatic Extraction Of Castor Oil

Ricinus communis L., sorted in Euphorbiaceae and Euphorbia, annual or perennial grass, usually is considered as an important oil plant. Comparing with other oil, castor oil is of excellent quality, such as high viscosity, low solidifying point, resistance to both low and elevated temperatures. Serving as a industrial oil plant, Castor oil is also a ideal feedstock for biodiesel.An aqueous enzymatic extraction technology was adopted to extract oil from castor seed. In order to provide a new way for comprehensive utilization and deep processing of castor, the optimal enzyme and enzyme complex on oil yield were investigated by multi-level optimization procedure. The optimum enzymatic hydrolysis conditions were obtained based on the response surface methodology, meanwhile the mechanism and the dynamic process of aqueous enzymatic extraction was investigated by using electron microscope and SEM. Finally, in order to compare the aqueous enzymatic extraction and the solvent extraction, the physicochemical property of castor oil of aqueous enzymatic extraction and the solvent extraction were studied too.The results were as follows:1Natural protease as the optimum enzymeThe optimum enzyme was chosen from cellulase, pectinase, amylase, natural protease, hemicellulase. The results showed that the natural protease was the best enzyme with the highest total oil extraction yield and the highest free oil extraction yield, up to82.22%and43.04%respectively.2The castor oil of aqueous enzymatic extraction with high quality and relatively good physicochemical property, in favor of subsequent refinery procedureThe experiment result showed that the color, impurity, saponification value and iodine value of the oil extracted by aqueous enzymatic method were better than those of the oil extracted by solvent and some physicochemical property was close to or even equal to the refined castor oil, which showed that the castor oil extracted by aqueous enzymatic method had relatively high purity and help to simplify the subsequent refinery procedure,3The optimum enzymatic hydrolysis conditions obtained by the single factor method and the response surface analysisBased on response surface methodology, the optimum conditions were found as follows:dosage of the enzyme3.5%, temperature50℃, hydrolysis time4h, pH value7.4, ratio of material to water1:4. The verification test showed that the oil yield of total oil and free oil could reach91.34%and64.92%at the optimum condition.4During the process of aqueous enzymatic extraction, cell wall and membrane of castor seed decompose gradually and dynamicallyBy means of frozen sections method, the result was found that the lipid granules were discretely distributed all around castor seed cells. By means of SEM, the intracellular and extracellular changes in castor seed cells during aqueous enzymatic extraction of oil were observed. The result showed that it was confirmed that natural protease was able to decompose cell wall effectively and release cell contents including lipid granules. From the morphological view. the decomposition of cell wall and cell membrane was a dynamic and gradual process.