Functional characterization of a new 3-dehydroshikimate dehydratase from Eupenicillium parvum and its potential for protocatechuic acid production.

Protocatechuic acid (PCA) is an important phenolic compound with diverse industrial values. Conversion of 3-dehydroshikimate (DHS) to PCA by dehydroshikimate dehydratase (DSD) provides an efficient approach for the production of the molecule. Herein, a new DSD from fungus Eupenicillium parvum was functionally investigated after recombinant expression in Escherichia coli. The DSD displayed 30%-35% sequence identities with the known fungal DSDs. The recombinant protein showed catalysis activity against DHS, with the optimal temperature of 40 °C and pH of 7.5. The specific activity and Km of the protein were 910 mU per mg protein and 0.83 m m, respectively. Metal ion (Mg2+ or Mn2+) played a critical role in the enzymatic activity. Meanwhile, the thermal stability of the protein was improved by Mg2+ or Mn2+. Furthermore, the expression of the protein in E. coli resulted in de novo synthesis of 491 mg/L PCA in a modified M9 medium with glycerol as a carbon source.