TECHNOLOGY FOCUS - BIOLOGY - Preferred Microorganism: The oil-producing thallus comprises Lipomyces starkeyi including strains AS2.1390, AS2.1560 and AS2.1608, Rhodosporidium toruloides including strains AS2.1389 and AS2.1609, Rhodotorula glutinis AS2.703, Mortierella isabellina AS3.3410, Rhodotorula mucilaginosa, Candida curvata, or Trichosporon cutaneum.    TECHNOLOGY FOCUS - CHEMICAL ENGINEERING - Preferred Method: The pretreated liquor is obtained by washing litchi slag, litchi seed and litchi rind, adding water, soaking for 0.5-1 hours, mixing, crushing, and screening using 40-80 meshes sieve. The acid hydrolysis is carried out by putting pretreated liquor in a reactor provided with stirring device, adding sulfate (0.1 mol/L), reacting at 125-135 degrees C for 2-3 hours under 2-3x 105 Pa. The detoxification process is carried out by adding macroporous resin soaked in absolute ethyl alcohol in ion exchange unit, and flowing hydrolyzed liquor in the resin bed under high temperature and pressure at a flow rate twice than that of the resin to eliminate furfural and phenol hydrolysate. The fermentation process is carried out by putting seed oil-producing microorganism liquid in the fermentation medium, culturing at 28-33 degrees C for 72-96 hours while agitating at 200-220 rpm. The Soxhlet extraction is carried out by centrifuging fermented liquor at 5000 rpm, drying at 100 degrees C, crushing into 100-mesh powder, putting in Soxhlet extractor, adding petroleum ether as extracting agent, heating, refluxing for 5-8 hours, removing extracted liquid by vacuum distillation, washing container for 2-3 times, and distilling to recycle solvent.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Material: The acid catalyst used during the ether exchange reaction comprises sulfate, phosphoric acid, hydrochloric acid, organic sulfonic acid solid acid and acidic ionic liquid catalyst.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Material: The short-chain alcohol is composed of methanol, ethanol, propyl alcohol, butyl alcohol and/or pentanol.