Fed-Batch Feed Calculator
Design a fed-batch feeding profile — exponential, linear, constant or step-wise bolus — with pump schedule, predicted biomass & volume, charts and safety warnings. Includes organism presets.
What is fed-batch?
In a batch culture every nutrient is added up front, so cells grow until substrate runs out or toxic by-products build up. In fed-batch you start with a small charge and feed concentrated substrate over time, keeping the limiting nutrient low and growth under control — avoiding overflow metabolism (acetate/lactate), reaching far higher cell densities, and lifting product yield.
What this calculator does
Choose a feeding strategy and it builds the pump schedule, predicts biomass & volume from a substrate mass balance, and flags safety risks. Turn on Compare strategies to overlay several profiles on the same charts.
Gold standard — holds a constant µ_set; minimises overflow metabolism.
Result: At µ_set 0.3 h⁻¹ (exponential feed) you reach 138 g/L in 12 h — using 6.5 L of feed, ending at 11.5 L, doubling every 2.3 h.
Detailed result & interpretation
- •Final 138 g/L is a genuinely high-cell-density result — typical fed-batch for E. coli runs 50–150 g/L DCW (batch alone reaches only 5–10; records ~190).
- •Exponential feed holds µ constant at 0.3 h⁻¹ (50% of µ_max), which keeps cells in their metabolic sweet spot and minimises overflow by-products. Acetate overflow sets in above µ ≈ 0.35 h⁻¹ (K-12) or 0.4–0.5 (BL21) — most high-density feeds hold µ_set at 0.1–0.3 h⁻¹.
- •Feed climbs from 64 to 1,735 mL/h (27.1× over the run) — size the feed pump and bottle for the peak rate, not the average.
- •Oxygen demand rises with biomass: at 138 g/L confirm your bioreactor's oxygen transfer (OTR/kLa), agitation and cooling can keep up — high-density cultures usually need enriched air/O₂.
- •Feed adds 6.5 L (volume 5 → 11.5 L). Enter a vessel working volume to check for overfill.
- •Next steps: validate against a bench run, then use the Upstream Sizing tool to scale this batch to your annual target.
Benchmarks from published high-cell-density literature: E. coli HCDC (Shiloach & Fass), Pichia fed-batch review, CHO VCD feeding. Figures are typical ranges — your strain/medium will differ.
Feeding schedule (Exponential)
| Time (h) | Feed rate (mL/h) | Cumulative feed (L) | Biomass (g/L) | Volume (L) |
|---|---|---|---|---|
| 0 | 64 | 0 | 10 | 5 |
| 1 | 64 | 0.064 | 12.8 | 5.06 |
| 2 | 86.4 | 0.15 | 16.6 | 5.15 |
| 3 | 116.6 | 0.267 | 21.4 | 5.27 |
| 4 | 157.4 | 0.424 | 27.6 | 5.42 |
| 5 | 212.5 | 0.637 | 35.5 | 5.64 |
| 6 | 286.8 | 0.924 | 45.2 | 5.92 |
| 7 | 387.2 | 1.311 | 56.9 | 6.31 |
| 8 | 522.6 | 1.834 | 70.6 | 6.83 |
| 9 | 705.5 | 2.539 | 86.1 | 7.54 |
| 10 | 952.3 | 3.491 | 103 | 8.49 |
| 11 | 1,285.5 | 4.777 | 120.5 | 9.78 |
| 12 | 1,735.2 | 6.512 | 138 | 11.51 |
Indicative feed model for planning. Assumes a single limiting substrate (all fed substrate consumed), constant yield, and no evaporation/sampling losses; real cultures deviate (induction, stress, O₂/CO₂ limits). Verify against your own run data and your bioreactor's oxygen-transfer and pump limits.
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