Abstract: The present disclosure relates to the technical field of biotechnology, in particular to carbonyl reductase mutant and its application. Specifically, the present disclosure provides a carbonyl reductase mutant for catalyzing the preparation of (R)-8-chloro-6-hydroxyoctanoic acid ethyl ester from 8-chloro-6-oxooctanoic acid ethyl ester. The mutant protein is a non natural protein and undergoes mutations in three core amino acids related to enzyme catalytic activity in the initial carbonyl reductase. The advantageous effect of the present disclosure is that the carbonyl reductase mutant provided by the present disclosure has the characteristic of efficiently catalyzing the preparation of the precursor substance (R)-8-chloro-6-hydroxyoctanoic acid from 8-chloro-6-oxooctanoic acid ethyl ester, and can efficiently catalyze the oxidation-reduction reaction of 8-chloro-6-oxooctanoic acid, with a product space-time yield of 99.9 g·L?1·h?1 or more.

Abstract: The present disclosure relates to the technical field of biotechnology, in particular to carbonyl reductase mutant and its application. Specifically, the present disclosure provides a carbonyl reductase mutant for catalyzing the preparation of (R)-8-chloro-6-hydroxyoctanoic acid ethyl ester from 8-chloro-6-oxooctanoic acid ethyl ester. The mutant protein is a non natural protein and undergoes mutations in three core amino acids related to enzyme catalytic activity in the initial carbonyl reductase. The advantageous effect of the present disclosure is that the carbonyl reductase mutant provided by the present disclosure has the characteristic of efficiently catalyzing the preparation of the precursor substance (R)-8-chloro-6-hydroxyoctanoic acid from 8-chloro-6-oxooctanoic acid ethyl ester, and can efficiently catalyze the oxidation-reduction reaction of 8-chloro-6-oxooctanoic acid, with a product space-time yield of 99.9 g·L?1·h?1 or more.

Abstract: Disclosed is a method for synthesizing (S)-nicotine and an intermediate thereof, which belongs to the field of synthesizing a heterocyclic compound. A chiral amino group is introduced into 4-hydroxy-1-(3-pyridyl)-1-butanone by transaminase chiral catalysis in the presence of an amino donor to obtain (S)-4-amino-4-(3-pyridyl)-1-butanol. An N-methylation reaction is performed on (S)-4-amino-4-(3-pyridyl)-1-butanol with a methylating agent to obtain (S)-4-(methylamino)-4-(3-pyridyl)-1-butanol. The intermediate is reacted with an acylating agent or a halogenating agent to convert an alcoholic hydroxyl group into a sulfonate group or a halogen. Finally, a ring closure reaction is performed to obtain (S)-nicotine in an alkaline condition. The raw materials are cheap and readily available, the reaction conditions are mild, the operation is simple, and the cost is low.