Abstract: An aptamer of nattokinase and method for screening the aptamer are provided, which relate to technical fields of biotechnology. A set of nattokinase nucleic acid aptamers screened by capillary electrophoresis separation technology is: SEQ ID NO:1˜SEQ ID NO:17. The dissociation constants of the seven aptamers were detected by surface plasmon resonance technology, and the affinity of the seven aptamers was strong, with affinities between 8.7-87 nM. The nucleic acid aptamer of the present disclosure has precise specificity, high affinity, and is convenient for chemical modification, and can be used as an effective molecular recognition tool for the high-sensitive analysis of proteins. it. The recognition technology based on nucleic acid aptamers provides a basis for the development of NK determination and efficient separation and purification.

Abstract: A liquid-liquid-liquid three-phase continuous and countercurrent extraction apparatus comprises a three-phase-mixing chamber, a three-liquid-flow settler, and a two-phase-mixing chamber; a liquid-flow control separator placed in the three-liquid-flow settler aims to flexibly regulate the directions of three liquid flows in the three-phase system by different control separator combinations to achieve either a countercurrent operation of the top-layered phase with the middle-bottom two-layered mixtures, or a countercurrent operation of the top-middle two-layered mixtures with the bottom-layered phase; and a method of using the same, relating to extraction and separation field of chemical technology.

Abstract: A liquid-liquid-liquid three-phase continuous and countercurrent extraction apparatus comprises a three-phase-mixing chamber, a three-liquid-flow settler, and a two-phase-mixing chamber; a liquid-flow control separator placed in the three-liquid-flow settler aims to flexibly regulate the directions of three liquid flows in the three-phase system by different control separator combinations to achieve either a countercurrent operation of the top-layered phase with the middle-bottom two-layered mixtures, or a countercurrent operation of the top-middle two-layered mixtures with the bottom-layered phase; and a method of using the same, relating to extraction and separation field of chemical technology.