TECHNOLOGY FOCUS - BIOLOGY - Preferred Components: The extraction material is oil producing seeds, cellulose material from transformation of wood and oleaginous plants, preferably rapeseed oil, sunflower, soybean, palm, canola, seaweed, castor, jatropha, Thlaspi arvense, mustard, flax, hemp, coconut (copra), maize, peanuts, rice, radish, jojoba, sesame, copaiba, cotton, poppy or Triadica sebifera. The extracted plant oil is 4-22C, preferably 16-18C fatty acid and its ester salt. The sub-critical is combined with at least an additional solvent for optimize the efficiency of the extraction of the plant oil. The additional solvent is ketone, alcohol, ester, ether, alkene, organic acid, organic halo compound and/or water. The sub-critical carbon dioxide is used in the two extraction. Preferred Method: The method comprises first extraction to extract and recover the plant oil from extraction material of one part and other part to enhance the cakes, and second extraction to proceed for refining or purifying the extracted plant oil during the first extraction step, where at least one of the extraction is conducted in the presence of sub-critical carbon dioxide. The sub-critical carbon dioxide extraction is carried out at a temperature of 15-40 degrees C, preferably 15-30 degrees C, and under a pressure of 50-100 bars, preferably 50-80 bars. The extraction process is not conducted in the presence of sub-critical carbon dioxide, is carried out using super-critical carbon dioxide, able to achieve the extraction of a compound with high added value comprising tocopherol, alkaloids, sterols, carotenoids, isoflavones, lecithin or vitamins. EXAMPLE - The extraction of rapeseed oil was carried out using sub-critical carbon dioxide as solvent. The primary extraction of oil was carried out using rapeseed and using sub-critical carbon dioxide, under a pressure of 70 bars and at a temperature of 25 degrees C. Then extracted oil was recovered. Then the second extraction was carried out using the recycled sub-critical carbon dioxide from the first extraction, under a pressure of 70 bars and at a temperature of 25 degrees C to refine the oil.