In fact, extraction and refining processes often account for more than half of the production cost of various biochemicals.For the vitamin K2 locating in the membrane, it is usually separated from the culture broth through organic solvent extraction after cell disruption. Luo et al compared different cell disruption methods to extract menaquinone-7, and they found acid heating and homogenization were two effective methods to improve theextract efficiency. Then the disrupted cell would be immersed into the extract solvents. Usually, an organic mixed solvent composing of 2-propanol and n-hexane (1:2 v:v) was used to extract menaquinone-7. Similarly, Tsukamoto et al. added different solvents separately, first adding 2-propanol and mixing for 15 min, followed by the addition of hexane and renewed mixing. Then, the mixture was dried and dissolved in 2-propanol for HPLC analysis. Wei et al. also tried to extract different menaquinones using a single organic solvent via three successive methanol extractions.However, the organic solvents have to be completely removed to ensure its safety, which results in complex downstream procedures and high processing costs. Therefore, some researchers aimed at eliminating the use of organic solvents and use the soybean oil as the replacement. An in situ recovery process was also proposed for menaquinone-7 production, in which vegetable oil was continuously added as the antifoaming agent and 80% of menaquinone-7 was extracted in the oil