Abstract: The present disclosure provides an innovative method for improving the enzyme activity of an NMN biosynthetic enzyme Nampt, and relates to the technical field of genetic engineering. A mutant protein of the present disclosure is obtained by firstly analyzing a target protein Nampt using two softwares FoldX and DeepDDG, and then predicting multiple key sites influencing the enzyme functions and finally performing the semi-rational design of the enzyme. In the examples of the present disclosure, 10 mutant strains are constructed using the designed primers according to the principle of point mutation, and 8 of the mutants have higher activity than a wild-type strain, in which the NMN yield of the mutant Nampt-V365L is increased by 62%, and the NMN yields of the mutants Nampt-S248A, Nampt-N164L, Nampt-S382M, Nampt-A245T and Nampt-A208G are increased by 34%, 27%, 27%, 22% and 17% respectively.

Abstract: The present invention provides a method for preparing a food fumeol, a method for preparing a food fumeol from Perilla frutescens as a raw material and application. The method for preparing a food fumeol includes: respectively preparing a single fumeol from each of n raw materials; and then, mixing at least two kinds of single fumeols to prepare the food fumeol, wherein n is a positive integer being greater than or equal to 2. According to application of the food fumeol, food is liquid smoked by using the food fumeol of the present application. The types and flavors of the food fumeol are greatly enriched, and the development of the food fumeol of different types and flavors is facilitated. A Perilla frutescens fumeol having a natural unique flavor prepared by the method for preparing the food fumeol from Perilla frutescens as the raw material contains rich flavor substances, and achieves antibacterial and antioxidant effects.

Abstract: The present invention provides a method for preparing a food fumeol, a method for preparing a food fumeol from Perilla frutescens as a raw material and application. The method for preparing a food fumeol includes: respectively preparing a single fumeol from each of n raw materials; and then, mixing at least two kinds of single fumeols to prepare the food fumeol, wherein n is a positive integer being greater than or equal to 2. According to application of the food fumeol, food is liquid smoked by using the food fumeol of the present application. The types and flavors of the food fumeol are greatly enriched, and the development of the food fumeol of different types and flavors is facilitated. A Perilla frutescens fumeol having a natural unique flavor prepared by the method for preparing the food fumeol from Perilla frutescens as the raw material contains rich flavor substances, and achieves antibacterial and antioxidant effects.