Using a mini-chromosome for synthetic biology in Pichia pastoris

Funding of just under £50k from IBioIC enabled Ingenza to gain invaluable expertise and enhanced their ability to access new markets and end users thanks to the technology developed as a result of this project.

Challenge

How to give Pichia the capability to produce ‘humanised’ proteins?

Glycoproteins are sugar-coated proteins which perform many different functions in the human body, from blood clotting to immune responses but they are also found on the surfaces of many viruses. Making and customising glycoproteins is therefore a key part of developing vaccines and other biotherapeutic treatments, however, the attached sugars have to be compatible with human biology to be useful, and they need to be produced at scale.

Pichia pastoris is a type of yeast which is cheap and reliable to grow at scale in simple facilities and is very capable of producing large amounts of human proteins. Despite these advantages, the glycoproteins it produces carry yeast-specific sugar molecules and this limits its usefulness for creating human therapeutics.

The team therefore had to find a way to change the sugar molecules that Pichia attaches to its proteins.

Solution

Mini-chromosomes solve the issue

IBioIC funding enabled Ingenza to work with University of Edinburgh’s Professor Paul Barlow to customise the manufacture of special proteins by yeast cells to serve a variety of industrial and biotherapeutic purposes.

Chromosomes are large and delicate DNA molecules that contain the cell’s genetic information. To achieve the attachment of humanised sugar molecules to proteins made in Pichia, a large number of extra, human genes would need to be inserted into Pichia’s existing four chromosomes. This would be complex and could disrupt the viability of the host cells.

Prof. Barlow’s team therefore introduced into Pichia cells a synthetic “mini” chromosome containing all the instructions needed for human glycoprotein production.

Outcome

Capabilities beyond glycoproteins

Ingenza gained expertise which, alongside the DNA libraries, tools, and strains, will be invaluable to the company as they expand their glycoprotein production capabilities. Perhaps more importantly, however, the knowledge gained in mini-chromosome production and use could transform biotherapeutic production at the company more generally. The technology developed as a result of this project has added to Ingenza’s biotherapeutic production capabilities, enhancing their ability to access new markets/end users.

“The knowledge generated in this project enabled Ingenza to identify additional commercial opportunities with which to expand its current P. pastoris biologics manufacturing platform and attract new commercial end-user partnerships”