Recommended technique
Separation handle: Charge separation, polishing.
Scope: Charge-based. CAPEX range: $150k-$1.5M.
Property comparison
| Property | Tryptophan | Lysine |
|---|---|---|
| Molecular weight | 204.23 Da | 146.19 Da |
| Solubility (water) | 11.4 g/L | 500 g/L |
| Charge | 0 | 1 |
| Isoelectric point | — | — |
| pKa | 2.38, 9.39 | 2.18, 8.95, 10.53 |
| Density | 1.37 g/cm³ | 1.35 g/cm³ |
| Diffusion coefficient | 6.20e-06 cm²/s | 7.80e-06 cm²/s |
| Log P | -1.06 | -3.05 |
Process design walkthrough
Define your feed stream
Set Tryptophan and Lysine as components with their concentrations and physical properties. Use the molecule database to auto-populate properties.
Drop in Ion Exchange
Connect the feed inlet, configure operating parameters (MWCO, pH, eluent, residence time as relevant), and connect the two outlets to product and waste streams.
Run the simulation
untangle.bio calculates outlet concentrations using mass balance and the separation function for this technique. Iterate on parameters to optimise yield vs purity.
Add polishing if needed
If the single step doesn't meet your purity spec, add a second separation with a complementary handle (e.g., size after charge, hydrophobicity after size).
Read more
Frequently Asked Questions
Why is Ion Exchange the right choice for this pair?
Ion Exchange exploits charge separation, polishing as the separation handle. The property gap between Tryptophan and Lysine on this axis is large enough to give a clean separation in a single step at industrially relevant flow rates.
What yield and purity can I expect?
Typical single-step recovery is 85-99% depending on operating conditions. Purity from a single ion exchange step is in the 90-99% range; polishing steps push above 99.5%.
What does this step cost to operate?
Capital cost for Ion Exchange at biotech scale is in the $150k-$1.5M range. Operating cost depends on scale, feed concentration, and product value. See the technique page for details.
How do I design this in untangle.bio?
Drop a ion exchange unit operation into the flowsheet, connect the feed stream containing both Tryptophan and Lysine, and the simulator will calculate mass balance and expected outlet concentrations using the molecule database properties.
Design this separation in untangle.bio
Build a flowsheet, simulate yield and purity, and estimate CAPEX for separating Tryptophan from Lysine.
Open untangle.bio