The invention relates to the field of
gene engineering, in particular to a
daidzein reductase mutant and application of the
daidzein reductase mutant in preparation of
equol, and the
daidzein reductase mutant is prepared by performing one or more of the following mutations on the basis of a
wild type: V263F, P107A, H351R, G35L, H171A, A267Q, H351Q, M355Q, H351P, G31V, V176A, H351Y, N64K, V137A, H351W, D63A, W257A and C174N. The catalytic activity of the mutant obtained through precise
mutation is remarkably improved under the
feedback inhibition condition, especially when high-concentration
equol exists, the mutant can still keep high relative activity, and continuity and high efficiency of the
biosynthesis process are ensured. When the mutant is applied to
biosynthesis of
equol, the production
titer is remarkably improved, the yield can be improved by about 1.2 times compared with that of a
wild type, and the economic benefit and the yield of
biosynthesis are directly improved.