Enhanced One-Step Fermentative Production of Epirubicin by Combination of Mutagenesis and Genetic Engineering in Doxorubicin-Producing Streptomyces peucetius
Epirubicin, a clinically important anthracycline-type antitumor drug, is industrially produced through a tedious chemical semisynthetic process. Here, we developed an engineered Streptomyces peucetius through a combinatorial strategy of strain mutation and metabolic engineering for efficient epirubicin biosynthesis. First, S. peucetius SIPI-DU-1557, which overproduces doxorubicin, was cultured through a doxorubicin-resistant screening method, and used as a host strain for genetic modification. Next, EvaE from Amycolatopsis orientalis, found through protein sequence comparisons of various exogenous TDP-4-ketoreductases, increased epirubicin production significantly. Subsequently, metabolic engineering strategies were used to enhance epirubicin production by co-expressing key biosynthesis pathway genes, dnrS/dnrQ and desIII/desIV, to strengthen metabolic flux toward epirubicin. The final epirubicin concentrations were 270 mg/L and 252 mg/L in the flask and 5 L fermenter, respectively. These are the highest levels reported, and show that the engineered S. peucetius has potential industrial application in green epirubicin production by direct fermentation with renewable resources.
Xiaoru Wang, Xiaorong Tian, Xiaofang Shen, Yuanjie Wu, Songbai Yang and Shaoxin Chen