Process Engineer - Protein Purification

Airtree recently invested in an early stage biologics company. Currently in stealth, they exist to make biologics radically cheaper, so modern medicine reaches the people today's industry prices out, across both human and animal health.

The Company

Discovery got cheap; manufacturing didn't. The cost of making biologics is now one of the biggest constraints keeping modern medicines from patients.

That is the constraint we exist to break.

We are building factories that deliver a 20-50x cost reduction at scale: more than 10 tonnes of drug substance a year, at under $10 a gram. Think of it as a foundry: a standardised manufacturing platform that molecules adapt to, rather than a contract manufacturer running a bespoke process for every client.

Our founding team has built a version of this before. We are now applying the same engineering playbook to biologics: standardise the hard parts, learn faster than everyone else, and make the economics work at a radically different scale.

We are looking for a Process Engineer to help build the purification platform that makes this possible.

Why this role exists

Biologics manufacturing is expensive because the hard parts are still too bespoke, too slow and too costly. Downstream purification is one of the biggest cost and learning gates.

This is not a role for someone who simply wants to run the standard mAb purification playbook. We need someone who can reason from first principles about chemical and physical interactions. You might come from biologics, but also might come from chemical engineering, chemistry, protein chemistry, industrial separations, membrane science, resin development, food or dairy protein fractionation, peptide purification, enzyme purification, colloid science or another adjacent field.

What matters most is not whether you have purified antibodies before. What matters is whether you can reason clearly about molecules, mixtures, interactions and experiments.

In your first 3-6 months, success looks like helping us rapidly test candidate purification architectures, identify the key interaction mechanisms and failure modes, define the analytical readouts that matter, and turn experimental learning into a reusable platform.

What you will own

You will help build a radically lower-cost biologics purification platform from first principles.

• Reason from the molecule and impurity profile upward: what is present, what must be removed, and what physical or chemical properties can be exploited
• Design fast, decision-oriented experiments to test separation mechanisms across chromatography, membranes, filtration, precipitation, buffer conditions and other approaches
• Build an understanding of how charge, hydrophobicity, size, binding affinity, solubility, aggregation, stability, ligand chemistry and surface interactions affect purification
• Develop simple experimental screens that tell us quickly whether a candidate process is worth pursuing
• Work with analytics to define the minimum useful readouts for each experiment: purity, yield, aggregation, host-cell protein, DNA, charge variants, product quality and impurity clearance
• Translate experimental results into platform rules, decision trees and operating windows
• Compare purification options quantitatively across yield, purity, clearance, buffer use, consumables, cycle time, robustness, scalability and cost per gram
• Help us reduce the number of bespoke steps, buffers and single-use consumables in the process
• Work shoulder to shoulder with upstream, analytics and process engineering so the purification process survives contact with real broth
• Help bring process-scale downstream equipment into reliable operation
• Challenge assumptions, including our own, about what biologics purification is supposed to look like

Requirements

Essential

• Strong technical foundations in chemical engineering, chemistry, physical chemistry, biochemistry, biomolecular engineering, materials science or a closely related field
• Excellent first-principles reasoning about chemical and physical interactions
• Ability to reason about complex mixtures: products, impurities, aggregates, host-cell proteins, DNA, media components, salts, buffers and other species
• Comfort thinking about charge, hydrophobicity, size, solubility, binding, adsorption, aggregation, membranes, ligands, surfaces and colloidal behaviour
• Strong experimental instincts: you can turn a hypothesis into a fast, well-controlled experiment with clear decision criteria
• Ability to interpret data and decide what to do next, even when the data is incomplete
• Enough analytical literacy to know what needs to be measured and why
• Hands-on attitude. You are happy building, testing, troubleshooting and learning in the lab
• High pace, high ownership and low ego
• Excitement about building a new platform, not inheriting an old one

Nice to have

• Experience with separations, purification, chromatography, filtration, membranes or adsorption
• Experience with proteins, peptides, enzymes, antibodies or other biomolecules
• Experience with AKTA / FPLC, HPLC, SEC, IEX, HIC, mixed-mode chromatography, membrane chromatography or TFF
• Experience with resin, membrane, adsorbent or ligand development
• Experience in industrial chromatography, food or dairy protein fractionation, enzyme purification, peptide purification or other adjacent separation fields
• Familiarity with biologics analytics such as SEC-HPLC, HCP ELISA, DNA assays, cIEF, charge variants, aggregation or product quality assays
• Process development or scale-up experience
• GMP, tech-transfer or regulated manufacturing exposure

Benefits