Two-step enzymatic synthesis of tyramine from raw pyruvate fermentation broth

•Tyrosine was prepared from pyruvate fermentation broth by tyrosine phenol-lyase.•Tyrosine was efficiently decarboxylated by immobilized tyrosine decarboxylase cells.•Tyramine hydrochloride was obtained with 99.9% purity and a total 86% high yield.•It is a green and economic strategy for the two-step enzymatic synthesis of tyramine.

Tyramine, as a metabolite of tyrosine, is an important intermediate in synthesizing some drugs and medicinal materials. In this study, an efficient method for producing tyramine was developed by a two-step biocatalytic reaction with recombinant tyrosine phenol-lyase whole cells and tyrosine decarboxylase immobilized cells. Raw pyruvate fermentation broth was used as substrate of tyrosine phenol-lyase to economically produce l-tyrosine. l-tyrosine was catalyzed by immobilized tyrosine decarboxylase cells to effectively synthesize tyramine. The conditions of two-step enzymatic catalysis reactions were optimized separately, and the influence of immobilization on tyrosine decarboxylase activity was investigated. In a scale up study, 94.3% l-tyrosine was obtained from raw pyruvate fermentation broth under the optimal conditions. l-Tyrosine was decarboxylated to tyramine with a high yield 91.2%. The total yield of tyramine could reach approximately 86% by this two-step biocatalytic reaction. This study provides us with a green strategy for efficient preparation of tyramine.

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