Towards the development of a Saccharomyces cerevisiae cell factory to produce the polyphenol 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. 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. Herein, we intend to understand if the GRAS yeast Saccharomyces cerevisiae is a suitable platform to genetically engineer towards curcumin biosynthesis. For that purpose, a combination of different curcumin biosynthetic pathways was designed and expressed in S. cerevisiae, and the curcumin production from supplemented ferulic acid was evaluated. The enzymes tested included Arabidopsis thaliana 4CL or feruloyl-CoA synthetase (FerA) from Pseudomonas paucimobilis and type III PKSs from C. longa (diketide-CoA synthase (DCS) and curcuminoid synthase (CURS)) or curcumin synthase (CUS) from Oryza sativa. The recombinant yeast strain that resulted in higher curcumin productivity was constituted by ferA, DCS and CURS reaching 1.8 mg/L of curcumin produced. 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.