Type: Full-time, Permanent | Salary: £48,000 – £62,000 + stock options | Location: Harwell, Oxfordshire, UK (in person) | Schedule: Mon–Fri, 37.5 hrs (flexible within 8am–6pm) | Eligibility: UK work authorisation required
KalvoTech is redefining bioprocessing with Prokitein™, our proprietary protein-based biopolymer. This breakthrough material enables edible hollow fibre membranes for a next-generation bioreactor platform designed to produce structured cultivated meat in a single step. Prokitein™ also opens new possibilities in novel foods, sustainable textiles and advanced materials. Join us in shaping the future of sustainable biomaterials production.
As our Principal Wet-spinning Engineer, you will own the wet spinning process at the heart of our technology: turning protein-based dope solutions into hollow fibre membranes and other materials that are reproducible, on-spec and scale. You will lead the materials team, define the fibre-spinning strategy, and work directly with the CTO and executive team to translate high-level vision into an actionable process roadmap – start to finish.
This is a high-impact leadership role where the right candidate will not only shape our core technology but also define how Prokitein™ fibres are made at scale. For an ambitious engineer or scientist, this role provides a clear path to becoming Head of Materials, with direct influence on product commercialisation, team expansion, and company growth.
Own and optimise our wet spinning process end-to-end:
- Develop protein-based dope formulations (solvents, concentration, additives, rheology) tuned for spinnability and target fibre properties.
- Run and develop the wet spinning platform for hollow fibres and materials: spinneret design and setup, extrusion, coagulation bath chemistry and conditions, take-up, washing and drying.
- Establish the relationship between spinning parameters and fibre outcomes – wall thickness, lumen geometry, porosity, mechanical strength – and use it to hit specifications reliably.
- Select and optimise crosslinking and post-processing strategies (chemical, physical) to tune mechanical properties, membrane morphology and stability.
- Characterise fibres and interpret results: tensile testing, SEM, FTIR, rheometry, porosimetry, permeability, protein assays.
- Lead troubleshooting on spinning defects and process drift, and drive continuous improvement of the line.
Lead the materials team, acting as line manager and technical authority, and setting the standard for how we plan, record and review experimental work.
Define and execute the wet spinning and materials strategy, working with the CTO and executive team to align long-term project goals and technical milestones.
Implement quality control processes to ensure fibres are produced on-spec, reproducibly and with full batch traceability.
Develop SOPs, risk assessments and protocols for the spinning line and post-processing, for internal R&D and for technology transfer to engineering and external partners.
Collaborate with engineering and external partners on spinning rig upgrades, multi-filament and continuous-line scale-up, and integration of our membranes into the bioreactor cartridge.
Run the materials lab: equipment, consumables, health and safety.
Remain hands-on, spinning fibres, running experiments, and analysing performance data alongside the team.
Why This Role is Exciting
- Real Ownership – You’ll own the wet spinning process behind the company's platform.
- Pioneer Sustainable Bioprocessing – Help develop a first-of-its-kind bioreactor platform that could transform cultivated meat production and unlock new applications for novel food and sustainable textiles.
- Build the Function – Set the standards, build the team, and define how a lab you'll lead for years actually works.
- Early-Stage Impact – Join early and directly shape the direction of our product, process, and company.
- Mission-Driven Work – Build a more ethical and sustainable food system through biomaterials innovation.
- Collaborative Culture – Work side-by-side with scientists, engineers, and founders in a supportive and fast-paced team environment.
Essential Qualifications and Experience
- Hands-on expertise in wet spinning (essential). Proven record setting up, running, and optimising a wet spinning line (spinneret selection, dope rheology, coagulation chemistry, draw/take-up). Note: Experience limited to electrospinning, spinning, or melt spinning alone will not substitute.
- 3+ years in polymer, fibre or biomaterials process development (or PhD + 2 years industry experience).
- Strong practical wet spinning and a working knowledge of protein chemistry and crosslinking methods.
- Proven experience leading experimental programmes: defining the question, designing the study, and being accountable for the conclusion.
- Experience leading teams and managing projects in a lab or process-development setting.
- Exceptional laboratory record-keeping — notebooks that someone else could repeat your work from a year later.
- Knowledge of quality control methods for materials production, and comfortable owning lab operations and health and safety.
- Hollow fibre spinning specifically (co-axial/annular spinnerets, bore fluid selection, lumen control).
- Hands‑on experience with protein‑based, plant‑derived or other bio‑based polymers.
- Scale‑up or tech transfer experience – taking a spinning process from bench to pilot or production, including multi‑filament or continuous lines.
- Experience with textile processing or downstream fibre handling (winding, drawing, drying).
- Membrane fabrication or porous material production.
- Familiarity with quality systems, GLP/GMP, or food‑contact material requirements.
- Experience contributing to patents, grant applications or technical reports.
- Advanced characterisation: SEM, FTIR, DSC/TGA, porosimetry, rheometry, protein assays.
What We Offer
- Full-time, permanent role starting as soon as possible
- Competitive salary & pension plan
- Stock options (EMI scheme) – share in our success
- 25 days annual holiday + bank holidays
- Bonus day off on or near your birthday
- Work at Harwell's world‑class science and innovation campus
- A collaborative, mission‑driven environment with real ownership
- Career growth and cross‑functional learning in a fast‑moving startup
We're a small, driven organisation that isn't afraid to think differently. We are looking for a like‑minded individual to join our team and help shape an emerging and ground‑breaking industry. As part of the team joining the founders, you will also have the opportunity to help shape the future of the company. Staying true to our slalom style, we move quickly from milestone to milestone to achieve our goals. As such, no two days at KalvoTech are the same. If this appeals to you, we would love to hear from you.
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