The first eukaryotic cell-free protein synthesis system to demonstrate linear scalability from 0.1 mL to 1,000 mL
| Overview ALiCE® is the first eukaryotic cell-free protein synthesis (CFPS) system to demonstrate linear scalability across a 20,000× range — from 0.1 mL microtiter plate reactions to 1,000 mL in a rocking-motion bioreactor — with no significant loss of protein yield. Both cytosolic and microsomal expression modes scale equivalently. All reactions run in simple batch mode: 24–48 hours at 20–25°C, lysate plus template DNA, with no continuous-exchange hardware. The commercial release specification is ≥2 g/L eYFP; target-dependent yields span roughly 0.1–3.5 g/L, and optimised large-scale process conditions have reached approximately 3 g/L. This scalability removes the process re-development step that normally separates early-stage protein engineering from preparative production. |
07 August 2026
Why Scalability Has Been the Defining Constraint for Eukaryotic CFPS
Cell-free protein synthesis offers rapid, open, flexible protein production without the constraints of cell viability. Its research utility has been recognised for decades across antibody discovery, vaccine antigen production, structural biology, biosensor development, and metabolic engineering [1, 2]. The field has nonetheless been held back by a persistent gap between laboratory demonstrations and manufacturing-relevant volumes.
The constraint has been sharpest for eukaryotic systems. Prokaryotic platforms — most notably the E. coli-based cell-free synthesis (XpressCF®) system developed at Sutro Biopharma — demonstrated scalability from 250 µL to 100 L as early as 2011, reaching 700 mg/L of rhGM-CSF across that range [3]. That result established that prokaryotic CFPS could support manufacturing-scale operations. It also established the ceiling: prokaryotic systems lack the eukaryotic secretory pathway, and therefore cannot deliver N-glycosylation, co-translational disulfide bond formation, or co-translational membrane insertion — the modifications that define most biopharmaceutical proteins.
Eukaryotic CFPS systems provide those capabilities but have historically been restricted to sub-millilitre or low-millilitre batch reactions [4]. The reasons are partly biological, since energy regeneration in eukaryotic lysates is more demanding, and partly practical, since producing eukaryotic lysate in quantity has been expensive. The consequence was that no eukaryotic CFPS system had been demonstrated meaningfully beyond the 10 mL scale until ALiCE®.
The Scalability Data: What Was Demonstrated
Das Gupta et al. presented systematic scalability data for the BY-2 lysate (BYL) system commercialised as ALiCE® [5]. Scaling experiments were performed using the same lysate batches across reaction volumes of 0.1, 10, and 100 mL. Both cytosolic expression (eYFP via pALiCE01) and microsomal expression (glucose oxidase via pALiCE02) were tested at every scale.
The reactions showed strikingly linear scalability across the 1,000-fold increase in reaction volume, with no significant loss in protein yield at the reaction endpoint, regardless of expression mode. The same result held for the simple cytosolic reporter and for the more demanding microsomal glycoprotein, confirming that the secretory machinery scales as reliably as the cytosolic translation apparatus.
The work was then extended to a 1,000 mL CELL-tainer® CT20 reaction for cytosolic eYFP production, run against concurrent 50 µL microtiter plate reactions. Comparison across the two formats showed no significant difference in protein yield across an overall scaling factor of 20,000× [5].
Subsequent internal development work has demonstrated that optimised large-scale process conditions achieve the expected high-productivity performance of the platform, including yields of up to 3 g/L. Taken together, these results support a straightforward conclusion: the same underlying ALiCE® reaction chemistry and workflow are maintained from microliter to liter scale, and scale-up is primarily a bioprocess engineering exercise in which oxygen transfer, mixing, and vessel geometry are aligned to the requirements of the reaction.
| Scale-up in ALiCE® is a bioprocess engineering exercise, not a re-optimisation of the biology. The reaction chemistry does not change between 50 µL and 1 L. |
The Biology Behind the Scalability: Why BYL Scales in Batch
The scalability of ALiCE® is rooted in the biology of the BY-2 cell lysate. Unlike CFPS systems that depend on an exogenous energy regeneration couple — phosphocreatine/creatine kinase, phosphoenolpyruvate, or an ATP-regenerating pair — BYL retains intact, functionally active mitochondria from the source cells [6, 7]. These regenerate ATP through oxidative phosphorylation, with glutamate-fed reducing equivalents entering the electron transport chain, providing a self-replenishing energy supply across the reaction.
Internal energy regeneration is why ALiCE® runs in batch mode — no continuous-exchange membranes, no semi-continuous feeding, no dialysis cassettes — and sustains synthesis for 24–48 hours. Continuous-exchange formats can extend the productive lifetime of a CFPS reaction, but they are difficult to scale, prone to membrane fouling, and expensive. The consequence for scalability is direct: a batch process in a standard vessel is far simpler to scale than a continuous or semi-continuous one [5, 7].
Oxygen transfer requirements are met at microliter scale by orbital shaking in microtiter plates, at millilitre scale by shaking in standard Erlenmeyer glassware, and at litre scale by the rocking motion of the bioreactor. Moving between scales requires appropriate vessel selection and oxygen transfer management — not changes in reaction chemistry, lysate concentration, or expression conditions [5].
What Linear Scalability Means in Practice
For protein engineering
The same 96-well format used for high-throughput variant screening at 50–100 µL delivers data that are directly predictive of yield at 100 mL or 1,000 mL. There is no inflection point and no requirement to re-characterise expression conditions at each new volume. A lead variant identified at microscale moves straight to a preparative reaction without intermediate process development.
For preclinical supply
Structural biology applications — cryo-EM sample preparation, crystallisation trials, solid-state NMR — need milligrams to tens of milligrams of purified protein. Mammalian cell culture typically requires stable cell line development of 4–8 months, followed by expansion and production runs, before that material exists. ALiCE® reaches preparative scale in under one week from plasmid, with no cell line development at all.
For manufacturing economics
The published process economics of CFPS manufacturing show that titre is the dominant cost driver: doubling titre from 1 to 2 g/L reduces cost of goods per gram by approximately 21% at an annual demand of 100 kg [8]. ALiCE®’s demonstrated yields, combined with the elimination of continuous-exchange processing, are directly relevant to that sensitivity. The productivity advantage over other eukaryotic CFPS systems in batch mode is a structural cost advantage that compounds with scale [7].
Comparison: ALiCE® Against Other Cell-Free Platforms
The following comparison is drawn from published platform data and the analysis in the LenioBio lab-to-GMP article.
| Platform | System type | Yield (batch) | PTMs | Glycosylation | Membrane proteins | Scalability | Primary use |
| Sutro XpressCF® | E. coli extract | 0.3–1 g/L | Limited | None | No | GMP / manufacturing | Clinical-stage ADCs |
| Wheat germ extract | Eukaryotic extract | 0.1–0.5 g/L | Limited | Minimal / inconsistent | Limited | mL-scale only | Research, HTP screening |
| PURExpress® | Reconstituted E. coli | <1 g/L | Limited | None | No | Not scalable | Mechanistic studies |
| PUREfrex® | Reconstituted IVTT | ~0.1–0.6 g/L | Engineered | Add-on demonstrated | Detergent / nanodisc | Preparative shown | Synthetic biology |
| ALiCE® | Eukaryotic plant CFPS | ~0.1–3.5 g/L | Yes | N-glycosylation* | Yes, endogenous | Multi-order scale-up | Complex proteins |
* ALiCE® microsomal reactions support co-translational translocation and N-glycosylation-associated processing in endogenous plant microsomes.
The Sutro OCFS system remains the most extensive scalability demonstration published for any CFPS platform, spanning roughly six orders of magnitude [3]. ALiCE®’s 20,000× range covers a smaller absolute span but achieves something qualitatively different: linear scalability for a eukaryotic system producing glycosylated proteins with co-translational membrane insertion. For antibodies, receptor ectodomains, cytokines, and membrane proteins, those modifications are not optional.
With the concept of ALiCE® reaction scaling proven, LenioBio has been working tirelessly to further scale ALiCE®towards the GMP-grade, cell-free biomanufacturing of protein-based medicines for human use. Here, we are proud to receive European Union co-funding for our InnoManContiMod project, whereby further scaling of the ALiCE® lysate process and CDMO enablement are key pillars of the project. InnoManContiMod will run until December 2027 and we look forward to sharing our advances in future updates (https://www.leniobio.com/eu-grant-info/).
Key Data
- Linear scalability: 0.1 to 100 mL using the same lysate batches, no significant yield loss at reaction endpoint
- 1,000 mL CELL-tainer® CT20 versus 50 µL microtiter plate: no significant yield difference, 20,000× overall scaling factor
- Both cytosolic (eYFP) and microsomal (glucose oxidase) expression modes scale equivalently
- Commercial release specification: ≥2 g/L eYFP reporter protein
- Target-dependent yield range: approximately 0.1–3.5 g/L
- Optimised large-scale process conditions: approximately 3 g/L demonstrated
- Reaction format: batch mode, 24–48 hours, 20–25°C, no continuous-exchange hardware
Frequently Asked Questions
Why is linear scalability in cell-free protein synthesis difficult to achieve?
Scalability requires that oxygen transfer, mixing efficiency, temperature control, and substrate concentrations stay consistent across every reaction volume. Most eukaryotic CFPS systems depend on exogenous energy regeneration couples that are hard to maintain at scale, and many require continuous-exchange formats that resist scaling by design. ALiCE® uses mitochondrial oxidative phosphorylation for self-sustaining energy regeneration in batch mode, so the reaction chemistry is identical at every scale and only the vessel changes.
What is the largest ALiCE® reaction volume that has been demonstrated?
A 1,000 mL reaction in a CELL-tainer® CT20 rocking-motion bioreactor, run against concurrent 50 µL microtiter plate reactions. Comparison of the two formats showed no significant difference in eYFP yield across an overall scaling factor of 20,000×. Optimised large-scale process conditions have subsequently reached approximately 3 g/L.
Does microsomal expression scale as well as cytosolic expression?
Yes. Both cytosolic eYFP expression via pALiCE01 and microsomal glucose oxidase expression via pALiCE02 were tested at 0.1, 10, and 100 mL using the same lysate batches. Both modes scaled linearly with no significant yield difference across the 1,000-fold volume range. This matters for membrane protein applications: it confirms that the microsomal machinery scales with the same reliability as the cytosolic translation apparatus.
How does ALiCE® scalability compare to the Sutro OCFS system?
The Sutro OCFS E. coli-based system demonstrated scalability from 250 µL to 100 L with yields of 700 mg/L — the largest CFPS scalability demonstration published. ALiCE® covers a 20,000× range but achieves what OCFS cannot: scalable production of glycosylated proteins with co-translational membrane insertion. For biopharmaceutical proteins requiring eukaryotic post-translational modifications, ALiCE® is the only published scalable option.
What yield should be planned around for a specific target protein?
The ≥2 g/L commercial specification refers to the eYFP reporter and functions as a batch quality indicator, not as a prediction for any given target. Target-dependent yields span approximately 0.1–3.5 g/L depending on sequence, folding requirements, and expression mode. Complex heteromultimeric proteins and multi-pass membrane proteins will sit lower in that range. The practical value of linear scalability is that whatever yield is measured in a microtiter plate is the yield that will be seen in a flask or a bioreactor.
Does the reaction need to run for the full 48 hours?
Reactions run in batch mode for 24–48 hours at 20–25°C. The optimal endpoint is target-dependent: some proteins reach maximum accumulation earlier, and for unstable targets a shorter reaction can give better recovery of intact protein. Running a timecourse on a small-scale reaction before committing to preparative volumes is worthwhile for any new target.
References
[1] Zawada JF et al. Cell-free technologies for biopharmaceutical research and production. Curr Opin Biotechnol. 2022;76:102719. https://doi.org/10.1016/j.copbio.2022.102719
[2] Gregorio NE, Levine MZ, Oza JP. A User’s Guide to Cell-Free Protein Synthesis. Methods Protoc. 2019;2(1):24. https://doi.org/10.3390/mps2010024
[3] Zawada JF et al. Microscale to manufacturing scale-up of cell-free cytokine production. Biotechnol Bioeng. 2011;108(7):1570–1578. https://doi.org/10.1002/bit.23103
[4] Tinafar A, Jaenes K, Pardee K. Synthetic Biology Goes Cell-Free. BMC Biol. 2019;17:64. https://doi.org/10.1186/s12915-019-0685-x
[5] Das Gupta M et al. ALiCE®: A versatile, high yielding and scalable eukaryotic CFPS system. bioRxiv. 2022. https://doi.org/10.1101/2022.11.10.515920
[6] Buntru M et al. Plant-Derived Cell-Free Biofactories for the Production of Secondary Metabolites. Front Plant Sci. 2022;12:794999. https://doi.org/10.3389/fpls.2021.794999
[7] Buntru M et al. Tobacco BY-2 cell-free lysate: an alternative and highly-productive plant-based in vitro translation system. BMC Biotechnol. 2014;14:37. https://doi.org/10.1186/1472-6750-14-37
[8] Stamatis C, Farid SS. Process economics evaluation of cell-free synthesis for the commercial manufacture of antibody drug conjugates. Biotechnol J. 2021;16:e2000238. https://doi.org/10.1002/biot.202000238
Funded by the European Union. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Health and Digital Executive Agency. Neither the European Union nor the granting authority can be held responsible for them.