Mining of Novel Myrosinase with High Activity Based on Sequence and Structure Clustering for Efficient Preparation of Sulforaphane

Sulforaphane has garnered significant research attention owing to its potent and promising biological activities. Mining the highly active myrosinase is the key to preparing sulforaphane. In this study, a novel myrosinase, designated Semyr, was identified from Serratia plymuthica through sequence and structural clustering analysis. The enzyme was heterologously expressed in Escherichia coli, demonstrating a sinigrin hydrolysis activity of 110.48 U/mg, which constitutes the highest recombinant myrosinase activity reported to date. A reaction system was established to prepare sulforaphane. 60 U of myrosinase was added to 5 mL of substrate, yielding 15.39 mg of sulforaphane per gram of broccoli seeds after 20 min at 40 °C and pH 6.0, with a conversion rate of 96.50%. Concurrently, the highest productivity of 5.55 μmol/g·min for sulforaphane was achieved after 15 min. Thus, Semyr serves as a valuable biocatalytic tool for the efficient preparation of sulforaphane.