The U.K.’s only commercial protein manufacturer to use an innovative plant-based expression system is hoping to boost the region’s biologics production capacity. Leaf Expression Systems, whose CEO Simon Saxby is due to speak about sustainable biotechnologies at the 19th Annual bioProcessUK Conference in November, says their goal is to supply the biologics industry by manufacturing at commercial scale.

“Right now, in the U.K., there isn’t a commercial-scale manufacturing facility for biologics, and I think [knowing we lack] that is one of the things that came out of the pandemic,” he notes.

According to Saxby, plant-based protein expression has been around for 30–40 years but is only now coming of age due to improved yields and an industry that needs to express a wider variety of proteins.

“Our industry is starting to grow now because our tech lends itself to expressing proteins that don’t express well in other systems, and that’s another string to the bow in terms of producing drug solutions for—for example—[tackling] a future pandemic,” he continues.

Plant-based expression systems can express large proteins, which can be hard to express in Chinese Hamster Ovary (CHO) or insect cells because plants are fully eukaryotic, which means they can process and fold large proteins more accurately than mammalian or bacterial cells, he explains.

Another benefit of using plants is that it’s easy to scale up the technology. “If you can express the protein in one plant, you know the protein expression from a million plants,” he says.

The power and infrastructure requirements of plants are also lower than traditional expression systems, he adds, as you don’t need steel or plastic bioreactors, and the plants can be composted.

Due to the lower manufacturing costs, Saxby says Leaf is working with St. George’s, University of London to develop a manufacturing process for anti-HIV antibodies. The idea is to manufacture them at low cost in low- and middle-income countries to help HIV-positive mothers avoid infecting their babies.

The company is also working to make their yields comparable with CHO cell-based expression systems. “You can produce multigram quantities of protein per liter with some of these products, and we’re not at that stage yet,” he says.