Biotransforming Phenylpropanoids derived from Biorefining:A Toolkit Approach

Project: Research project (funded)Research

Project Details


Phenylpropanoids (PPs) are a group of metabolites found in all terrestrial plants which are used in nature to make a range polyphenolic compounds, which serve important dietary functions as flavourings and antioxidants. In this project, we propose to effectively copy the pathways which exist in nature and take PPs left over as low value by products of biofuel and plant fibre production and biotransform them into high value chalcone, aurone and stilbene polyphenolics. This biosynthetic process would be carried out in fermentable microbes, using enzyme pathways which can be assembled together in a modular manner to generate a wide range of end products from the limited range of PPs available from biorefining. In addition to generating existing known antioxidants and flavourings, the ability to increase the production of unusually biologically active intermediates, such as dihydrochalcones, has the potential to produce unique flavourings and neutraceutical agents. To illustrate the technology, we will generate glycosylated dihydrochalcones which are 100s of time sweeter than sucrose and used as flavour enhancers, without resorting to harsh chemical reactions.
The proposed process involves a series of individual enzyme steps , each of which serves as a module which can then be linked to the next biosynthetic step to produce the compounds of interest. The first committed step in the pathway involves the generation of a common precursors (Work package 1= WP1) which can then be converted to a range of polyphenolic metabolites depending on the enzyme used (WP2). The resulting compounds can then be structurally modified with sugars (WP3) to give the biologically active end products. Then to illustrate how this approach can fast forward the biological production of unusual and low abundance neutraceuticals, we will use the same WP1-3 linked approach to generate a second generation of polyphenolics based on benzoic acid precursors which are also extracted from plants. The programme would be conducted at Durham University over a three year period in the interdisciplinary Centre for Bioactive Chemistry .
In addition to expanding the existing markets for plant-derived chemicals used in high value food applications, the project has the potential to generate completely new products which have good chemical precedence as being biologically active and usable by industry. In addition the project further improves the sustainability of biofuels and other mainstream ‘green’ refined plant products by increasing the value of the main process by transforming low value waste-streams into high value chemicals for food applications.

Layman's description

The use of plants as renewable feedstocks to replace petrochemicals requires similar levels of efficiency in terms of refining and recovery of useful products. In biofuel production, which is currently the most advanced refining applied to recover platform chemical from plant biomass, a considerable amount of material is non-fermentable and remains as a low value by-product at the end of the process. Fractionating this residue and adding value to its components would enhance the efficiency economics and ultimately sustainability of biorefining. One relatively abundant and easily recoverable chemical in the non-fermented material is the secondary metabolite ferulic acid, a phenylpropanoid (PP) used extensively in plants for making biologically active polyphenolic compounds. In this project we propose to use ferulic acid and other PPs as precursors to produce dihydrochalcones and their glycosylated derivatives through fermentation in metabolically engineered yeast. These dihydrochalcones are widely used as artificial sweetners and flavour masking agents in the food industry and are currently made by non-chemical transformation methods. In our process, we will reconstruct pathways which function to produce polyphenolics in plants and engineer them into yeast, which on feeding with PPs will then produce these artificial flavouring agents through a sustainable biological process. As artificial flavouring agents, the use of genetic modification to produce these compounds will not affect their market value, as they are not ‘natural’ products. Furthermore, the modular assembly of our engineered pathway and the feeding of specific PP pre-cursors gives us the potential to produce novel dihydrochalcones which have the potential to be developed into new flavour enhancing products for the food industry. The programme therefore will therefore add value to existing fermentation processes which utilise plant material. In addition the process would also be highly compatible with processes aimed at deconstructing lignin, which is a major non-fermentable product derived from woody biomass composed of PP intermediates. Thus the project is both of immediate utility and establishes useful technologies of longer term value to the biorefining industries which have identified lignin deconstruction and the use of the respective products as a major future commercial opportunity.
Effective start/end date24/01/1123/07/14