HotHouse Therapeutics Emerges with £2.9M to Revolutionize Plant-Based Drug Manufacturing Using AI
Key Insights
HotHouse Therapeutics (search) secured £2.9 million in pre-seed funding to develop an AI-enabled plant bioengineering platform that transforms plant leaves into chemical factories for drug production.
The company aims to address critical vaccine supply constraints by producing QS-21 adjuvant through bioengineered plants, replacing dependence on slow-growing Chilean soapbark trees.
The platform combines AI-powered design tools with transient plant expression systems to unlock over 20 million novel molecules for pharmaceutical applications.
HotHouse Therapeutics (search) has emerged from stealth with £2.9 million in pre-seed funding to advance an AI-enabled plant bioengineering platform that aims to transform how modern medicines are discovered and manufactured. The Norwich-based startup secured investment from SynBioVen (search), Start Codon (search), UKI2S (search), Twin Path Ventures (search), Wren Capital (search), multiple angel investors, and an Innovate UK grant.
The company is using its newly revealed platform to address one of the vaccine industry's most persistent supply constraints: global dependence on a single, unsustainable source of the critical adjuvant QS-21. At present, QS-21 is derived from the bark of a slow-growing Chilean tree, resulting in a fragile and resource-intensive supply chain that cannot meet rising international demand and disproportionately affects low- and middle-income countries.
Revolutionary Plant-Based Production System
HotHouse Therapeutics (search) aims to replace this bottleneck with bioengineered plant systems that can be grown efficiently and cost-effectively anywhere. Its platform combines AI-powered design tools with a transient plant expression system that reprograms plant leaves into miniature chemical factories capable of producing both natural and novel molecules in days.
The company's BotanAI design engine works with its BotanBIO production system to rapidly generate high-purity, single-entity compounds. The approach creates a carbon-positive, scalable production pathway suited for global health applications that require predictable supply and improved affordability.
Scientific Foundation and Leadership
The scientific foundation for the platform is based on the work of Professor Anne Osbourn OBE, FRS, Novozymes Prize Laureate 2023, and an international member of the US National Academy of Sciences, who serves as the company's chief science officer. Her research has demonstrated that complex molecules such as QS-21 can be fully biosynthesised in plants.
One of Osbourn's recent academic achievements was elucidating the entire biosynthetic pathway for the vaccine adjuvant QS-21. "Synthetic chemistry is not delivering new therapeutics at the rate that it needs to . . . whereas plants are chemical engineers par excellence, and they make a huge array of diverse chemistry," says Osbourn.
Addressing QS-21 Limitations
QS-21, which helps stimulate the immune system, is a component of the Shingrix shingles (search) vaccine, among other vaccines. However, the difficulty of sourcing soapbark and extracting QS-21 has made the compound expensive. According to Osbourn, QS-21 is far from a perfect adjuvant. "It is a potent immunostimulant, but it's quite toxic to human cells," she says.
HotHouse is using Osbourn's knowledge of the QS-21 pathway to make the molecule in Nicotiana benthamiana, a relative of tobacco often used in plant biotechnology. The firm is also leveraging its AI platform to tweak the pathway to create related molecules, hoping pharmaceutical companies will test their products on the related molecules to find an ideal adjuvant for their purposes.
Platform Capabilities and Future Applications
The company reports that its system can currently unlock over 20 million novel molecules by combining AI-driven pathway prediction with the enzymatic diversity found across the plant kingdom. Its production approach is designed to support vertical farming infrastructure and long-term sustainability metrics, offering an alternative to extractive or resource-intensive chemical manufacturing.
While its initial focus is on next-generation saponin-based vaccine adjuvants, including sustainable sources of QS-21, QS-7, and a growing library of novel derivatives, HotHouse also plans to expand into traditional drug discovery programs by advancing new assets through clinical development.
Commercial Strategy and Timeline
HotHouse will pursue multiple commercial strategies, including exclusive supply of high-value adjuvant chemistry, access to its adjuvant panels for researchers and developers, and bespoke discovery partnerships with pharmaceutical and biotechnology companies. Early preclinical comparisons between the company's adjuvant candidates and QS-21 are expected to inform upcoming collaborations with global health organisations, vaccine developers, and biopharma firms.
CEO David Sheppard emphasizes the company's broader vision: "We are not a vaccine adjuvant company. We are a platform company." HotHouse is producing QS-21 and the analogs as a proof-of-concept and its first revenue-generating project, with the long-term goal of producing entirely new compounds useful for myriad pharmaceutical purposes.
Sheppard says HotHouse intends to have its next funding round in early 2026 and to use that money to mature its drug discovery program. "We grow greener medicines using a platform that makes the impossible accessible," he states. "The drug discovery field desperately needs new chemical space and the vaccine field needs new adjuvants, with supply chains that work for everyone."