Metabolic engineering of Saccharomyces cerevisiae for productionof curcumin

Abstract

Curcumin, a polyphenol produced by turmeric (Curcuma longa), has attracted increased attention due to its potential as a novel cancer-fighting drug. However, to satisfy the required curcumin demand for health-related studies, high purity curcumin preparations are required, which are difficult to obtain and extremely expensive. Curcumin accumulates in low amounts over long periods in the plant and its extraction process is costly and not environmentally friendly. In addition, its chemical synthesis is complex. All these reasons block the advances in studies related to the in vitro and in vivo curcumin biological activities. Herein, we intend to develop a genetically engineered Saccharomyces cerevisiae capable of producing pure curcumin from simple carbon sources such as glucose. The curcumin biosynthetic pathway in plants starts with the phenylpropanoid pathway, whose reactions convert the aromatic amino acids (phenylalanine/tyrosine) to the curcumin precursor ferulic acid. Afterwards, curcumin is produced under the catalysis of 4-coumarate-CoA ligase (4CL) and type III polyketide synthases (PKSs) with the involvement of one malonyl-CoA molecule. As starting point for the development of a yeast cell factory, we tested the curcumin production using 2- micron plasmid vectors carrying the 4CL1 from Arabidopsis thaliana and the PKS curcuminoid synthase (CUS) from Oryza sativa in a wild-type S. cerevisiae strain. This modified strain was able to produce 55 µg/L of curcumin from supplemented ferulic acid. In the future, additional genetic modifications will be constructed in the yeast chassis to increase the natural supply of precursors, such as malonyl-CoA, and consequently the curcumin productivity. Additionally, the enzymes from phenylpropanoid pathway will be included in the heterologous pathway to allow the use of simpler substrates.