Project title: Optimisation of strain and culture conditions of the microalga, Chlamydomonas reinhardtii, for recombinant protein production from nuclear transgenes.
Supervisors: Professor Peter Ralph and Dr. Audrey Commault
Project background: Microalgae are single celled organisms widely known for their commercial applications in production of biofuels, nutraceuticals, feed for animals and aquaculture. Nowadays, microalgae are emerging as a new platform for recombinant protein production, as they offer many advantages as compared to other prokaryotes, mammalian cells and yeast. Prokaryotes like bacteria lack post-translational modifications which is crucial for protein folding, protein-protein interactions, stability and optimal pharmacokinetics.
Moreover, bacterial production systems also require complex purification steps which increase the cost of the process, whereas microalgae protein can be expressed in a bioavailable form as most of the microalgae are “generally regarded as safe” (GRAS). Expensive cultivation medium for mammalian cells does not allow them to be economically viable for recombinant protein production. Yeast production systems give very low yield and have only specific post translational modification mechanisms.
Therefore, microalgae are increasingly being considered for recombinant protein production because of their low cultivation costs and presence of post translational modification mechanisms. Despite of all the advantages, microalgae are still struggling in their initial years to become commercially viable tools for recombinant protein production. Therefore, in this PhD project, the microalga Chlamydomonas reinhardtii will be used to increase the yield of recombinant protein (Interferon alpha 2A) from nuclear transgenes. Interferon alpha-2A is a human protein encoded by the IFNA2 gene. Recombinant IFNα2 (α2a and α2b) has anti-cancer and anti-viral properties (Paul et al. 2015). It has been chosen in this study, because it is small (19.2 kDa) in size, soluble (easy to extract), and has been produced in other expression systems (bacteria, CHO cells, etc), making it possible to compare the activity and stability of algal interferon to others.
Funding: UTS International Research Scholarship and UTS President’s Research Scholarship