A synthetic biology approach to engineering novel commercial variants of cyanobacterial pigment proteins

Cyanobacteria are an established bioplatform for the production of commercially important pigment proteins, such as phycoerythrin and C-phycocyanin (C-PC), which are used widely in the food, nutritional, analytical and pharmaceutical industries(1). Scottish Bioenergy (www.scotbio.com/) view C-PC as an outstanding candidate for exploitation and aims to produce high-quality C-PC at industrial scale. Scottish Bioenergy has already invested in significant R&D to improve upstream and downstream processing and to produce new cyanobacterial strains with increased C-PC yields. Structurally, C-PC consists of a covalently bonded complex of two apoproteins and phycocyanobilin chromophores, which together form the most abundant pigment protein of the light-harvesting phycobilisome complex(2). However, C-PC is both heat- and light-sensitive, which places considerable constraints on storage and usage. This project proposes to use a synthetic biology approach to engineer commercially relevant cyanobacterial strains to produce new variants of C-PC with increased thermotolerance, light resistance and improved fluorophore properties(3). Synthetic C-PC variants will reduce downstream costs and are predicted to have significant market value.

Training

This project is an outstanding training opportunity to engage with a wide variety of molecular and physiological approaches, and to be involved in commercial translation activities. You will develop expertise in cyanobacterial-based molecular skills, including DNA, RNA and protein analyses (e.g. qRT-PCR, Western blot, ion exchange chromatography), and photosynthetic physiology and fluorescence techniques. The project will employ directed evolution approaches to evolve proteins involved in C-PC biosynthesis for C-PCs with improved characteristics. Promising protein variants will be integrated into commercially relevant strains to test their performance and physiological impact. Thus, you will engineer, test and model the performance of new cyanobacteria strains expressing industrially favourable C-PC forms. There will be abundant opportunity for you to present your research at regular meetings, including national and international conferences.

Integration with Scottish Bioenergy and Alignment to the UK Industrial Strategy

The outlined project links directly with the commercial goals of Scottish Bioenergy. Novel pigment producing strains will be tested first under lab conditions, and then at pre-commercial scale with Scottish Bioenergy. The candidate will maintain close ties through regular planned monthly meetings, to discuss progress. The candidate will perform a dedicated 3-month placement at Scottish Bioenergy in year 4 (first or second quarter) of the project to test the performance of the most promising strains under pre-commercial quantities. Growth and product yields will be compared under light and temperature conditions optimised in lab-based bioreactors. The project is directly relevant to several of the pillars of the UK industrial strategy: research that will directly contribute to commercialisation of a high value product, skills development, supporting businesses to grow, and cultivating world-leading sectors (Scotland has a growing IB sector for industrial scale production of microalgae and a strong allied academic sector).

Lab website: http://mccormick.bio.ed.ac.uk/