Senior Downstream Process Engineer

About Nūmi

Nūmi is a bioproduction platform harnessing human mammary cells to produce key ingredients with proven health benefits across all stages of life. More specifically, it is the first European cultivated breast milk company aiming to produce human milk constituents to better match the ideal nutrition for babies. We are an early-stage, VC-backed biotech based in the heart of Paris (Hôpital Cochin, Paris 14th) and supported by world-class investors and scientific partners.

Nūmi's Values

Positivity: At Nūmi, we cultivate positivity every day. Our mission drives us to communicate with passion and energy, always keeping the bigger impact in sight. We celebrate quick wins, but never lose track of our ultimate goal.

Excellence: At Nūmi, excellence starts with dedication and a commitment to constant improvement. We embrace challenges as opportunities to learn and push ourselves to deliver high-quality results. Through effort, attention to detail, and integrity, we grow both individually and collectively as a team.

Team-Work and Pedagogy: At Nūmi, we believe that teamwork makes us stronger. We encourage knowledge-sharing, open feedback, and mutual respect. Each Nūmiz is here to lift others up, ensuring that the collective succeeds.

Ambition: At Nūmi, we set ambitious goals and challenge ourselves to think big. Nūmi is driven by bold ideas and relentless determination, always aiming for the stars to create real impact.

Why this role matters

As Nūmi scales its ingredient portfolio (proteins, human milk oligosaccharides, functional lipids) from bench through pilot to first industrial batches, we are looking for a Senior Downstream Process Engineer to own our purification strategy hands-on. Reporting to our Head of Industrialisation and working closely with our Head of USP, our Reg & QC Implementation Lead and our CMC Lead, you will be the senior technical anchor for our DSP function, and you will mentor a team of DSP Engineers.

This is a role for someone who has spent a decade or more purifying complex biomolecules from fermentation broths, cell culture supernatants or milk fractions, and who now wants to build a first-of-its-kind DSP platform from the ground up.

Key Responsibilities

Own the DSP Strategy and Roadmap

• Define and deliver Nūmi's downstream process strategy across the ingredient portfolio (proteins, oligosaccharides, functional lipids).
• Own the DSP scale-up trajectory from lab scale through pilot and toward first industrial batches.
• Design and refine unit-operation sequences (clarification, capture, intermediate purification, polishing, formulation, drying) tuned to each ingredient.

Lead Hands-On Process Development

• Design, execute and interpret experiments on chromatography (ion exchange, affinity, hydrophobic interaction, size exclusion, simulated moving bed), membrane operations (MF, UF, DF, TFF, nanofiltration), centrifugation, precipitation, spray or freeze drying.
• Apply DoE and QbD approaches to identify critical process parameters and build robust process characterisation packages.
• Establish scale-down models to derisk scale-up decisions.

Team Building and Mentorship

• Mentor mid-level DSP Engineers and interns.
• Foster a culture of transparency, scientific rigour and rapid iteration.

Scale-Up and Tech Transfer

• Support scale-up from lab (2-5 L) through pilot (50-200 L) toward commercial scale whether in-house or via CDMOs.
• Prepare technology transfer dossiers and lead on-site oversight when working with external manufacturing partners.
• Own the technoeconomic analysis of DSP unit operations : yield, purity, cost, throughput.

Cross-Functional Collaboration

• Partner with Head of USP on interface points (harvest strategy, feed composition impact on DSP).
• Partner with our CMC Lead on release specifications, comparability protocols and stability data supporting the Novel Food dossier.
• Partner with our Reg & QC Implementation Lead to ensure DSP methods are inspection-ready and aligned with agency expectations.

Requirements

Experience & Knowledge

• MSc or PhD in bioprocess engineering, chemical engineering, biochemistry or a related discipline, with 10+ years of hands-on downstream process development experience.
• Deep expertise in purification of sugars (HMOs, oligosaccharides), recombinant proteins from microbial or fungal fermentation, or milk ingredients (lactoferrin, whey proteins, casein) from bovine milk is highly valued.
• Track record of scaling at least one DSP process from bench through pilot toward commercial scale.
• Strong command of chromatography, membrane operations, filtration, drying, and formulation unit operations.
• Comfortable with DoE, QbD, process characterisation, technology transfer to CMOs/CDMOs.

Leadership & Judgement

• Prior experience mentoring or leading DSP scientists and engineers.
• Strong critical thinker who is comfortable solving unique scientific challenges by learning from peers, seminars and scientific literature.
• Ability to translate technical process decisions into regulatory-defensible documentation.

Communication

• Strong verbal and written communication skills in English.

Bonus

Ideally you have experience in some, but not necessarily all, of the following areas :

• Precision fermentation, plant biomass fermentation, or milk ingredient purification.
• Novel food dossier support or biologics filing support.
• Sanitary process design (HACCP, food-grade).
• Spray drying, freeze drying, formulation of powdered ingredients.
• Simulated moving bed (SMB) chromatography for sugars.
• Aseptic technique in biosafety cabinets and cGMP-adjacent environments.
• Startup or scale-up environment (Series A to C).

Benefits

Unique opportunity to be one of the first senior hires at an early-stage biotech company, shaping the future of infant nutrition.

Growth opportunities : you will have the opportunity to grow with the company and shape the Bioprocess organisation as it scales.

Access to top-quality facilities, research services and infrastructure.

Competitive salary, ESOP, part health insurance coverage, part transportation and lunch coverage.

⭐ Employee-first mentality, we prioritize the well-being of our team members, both in terms of their mental and physical health.

Recruitment process

• Initial skills matching.
• First interview with our cofounder and CTO Eugénie.
• A technical case study to assess your understanding of DSP scale-up and process characterisation.
• A last interview on-site to meet our cofounder and CEO Eden, part of the team and visit the labs.
• 2 to 3 reference calls.

Nūmi is committed to building a diverse and inclusive workplace. We welcome applications from people from all walks of life.