Propagation Medium Composition Calculator

Saccharomyces cerevisiae Biomass

The Propagation Medium Composition Calculator is a self-contained, browser-based tool by FermAxiom LLC for formulating chemically defined media for aerobic Saccharomyces cerevisiae biomass propagation. It runs entirely client-side in vanilla JavaScript with no server or installation required, updating all results in real time as inputs change.

Every nutrient quantity derives from first principles — the elemental composition of the target yeast biomass and the biomass yield on glucose (Yₓ/ₘ). Users set batch and fed-batch biomass targets, a final DCW concentration, and a yield coefficient; the tool derives volumes, phase splits, and glucose allocations across a fully editable 22-element composition table covering macroelements, trace metals, and vitamins. A two-pass salt algorithm converts element requirements into compound masses, then automatically credits co-delivered nutrients, while a toggleable utilisation efficiency correction compensates for real-world losses like ammonia volatilisation and vitamin degradation.

The calculator also generates five stock solution preparation sheets per phase with EDTA auto-calculation and solubility warnings, an 11-step cultivation procedure with all values computed live, a batch medium concentration check against published inhibitory thresholds, and a reverse "Test Medium" mode where users enter available compounds to identify the limiting nutrient and maximum achievable biomass.

Propagation Medium Composition Calculator — Saccharomyces cerevisiae Biomass

Propagation Medium Composition Calculator
for Saccharomyces cerevisiae Yeast Biomass

Batch + Fed-Batch Mode • Stoichiometric Calculation • Real-time

Target Production

Batch Phase — Target Dry Biomass

g DCW

Fed-Batch Phase — Target Dry Biomass

g DCW

Final Biomass Concentration

g DCW/L

Biomass Yield on Sugar (Y_X/S) 0.48 g/g

Total Target Biomass 1000 g DCW

Total Broth Volume 20.0 L

Apply utilisation efficiency correction ON

Biomass Composition (editable)

Element / Compound	Min.	Max.	Unit
Macroelements
Nitrogen (N)	5	10	%
Phosphorus (P)	0.8	2.4	%
Potassium (K)	0.6	2.5	%
Magnesium (Mg)	0.1	0.5	%
Sulfur (S)	0.3	0.6	%
Calcium (Ca)	0.02	0.15	%
Sodium (Na)	—	0.5	%
Trace Metals
Iron (Fe)	100	500	mg/kg
Zinc (Zn)	50	250	mg/kg
Manganese (Mn)	50	200	mg/kg
Copper (Cu)	10	80	mg/kg
Molybdenum (Mo)	0.1	1	mg/kg
Cobalt (Co)	0.1	2	mg/kg
Vitamins
Biotin (B8)	0.05	0.25	mg/kg
Thiamine (B1)	20	150	mg/kg
Riboflavin (B2)	20	80	mg/kg
Nicotinic A. (B3)	100	600	mg/kg
Pantothenate (B5)	50	100	mg/kg
Pyridoxine (B6)	5	60	mg/kg
Folic A. (B9)	10	40	mg/kg
Inositol (B8)	3000	10000	mg/kg

Total Sugar Required

2083

g fermentable sugars

Total Target Biomass

1000 g

Batch 400 g

Fed-Batch 600 g

Final Volume

20.0 L

at 50 g DCW/L

Compound	Salt / Note	Total Required	Unit

Initial Batch Phase Medium

Compound	Total in Batch	Conc. (g/L)

Fed-Batch Feed

Compound	Total to Feed	Unit

Cultivation Procedure

Reference Data

S. cerevisiae Biomass Composition — Literature Values

Element / Compound	Typical value	Min.	Max.	Unit	Notes
Macroelements
Carbon (C)	47	44	52	% dry wt	Largest elemental fraction; not supplemented
Nitrogen (N)	8.3	5	10	% dry wt	Decreases at high C:N or N-limitation; ~80% protein-N
Oxygen (O)	31	28	34	% dry wt	Structural; not supplemented directly
Hydrogen (H)	6.5	6	7	% dry wt	Structural; not supplemented directly
Phosphorus (P)	1.2	0.8	2.4	% dry wt	Nucleic acids, ATP, phospholipids; growth-rate dependent
Potassium (K)	1.0	0.6	2.5	% dry wt	Major intracellular cation; osmotic regulation
Sulfur (S)	0.4	0.3	0.6	% dry wt	Cysteine, methionine, glutathione, coenzyme A
Magnesium (Mg)	0.4	0.1	0.5	% dry wt	Ribosome stability, enzyme cofactor; often limiting
Calcium (Ca)	0.05	0.02	0.15	% dry wt	Signalling, cell wall
Sodium (Na)	0.1	—	0.5	% dry wt	Non-essential; toxic at high concentrations (> 0.5 M)
Trace Metals
Iron (Fe)	250	100	500	mg/kg DCW	Cytochromes, Fe-S clusters; chelated forms improve bioavailability
Zinc (Zn)	120	50	250	mg/kg DCW	RNA polymerase, alcohol dehydrogenase; second-most abundant trace metal
Manganese (Mn)	120	50	200	mg/kg DCW	SOD, glycosyltransferases; Golgi-resident enzymes
Copper (Cu)	30	10	80	mg/kg DCW	Cytochrome c oxidase, Cu/Zn-SOD; toxic > ~1 mM
Molybdenum (Mo)	0.4	0.1	1	mg/kg DCW	Sulfite oxidase cofactor; ultra-trace requirement
Cobalt (Co)	0.5	0.1	2	mg/kg DCW	Vitamin B12 precursor
Vitamins
Biotin (B8)	0.15	0.05	0.25	mg/kg DCW	Growth-limiting in defined media; carboxylase cofactor; cannot be synthesized by most strains
Thiamine (B1)	10	20	150	mg/kg DCW	TPP cofactor for pyruvate decarboxylase; synthesized by yeast but often supplemented
Riboflavin (B2)	40	20	80	mg/kg DCW	FAD/FMN; synthesized by yeast; high in spent biomass
Nicotinic A. (B3)	300	100	600	mg/kg DCW	NAD⁺/NADP⁺ precursor; synthesized from tryptophan; abundant in yeast
Pantothenate (B5)	50	50	100	mg/kg DCW	Coenzyme A biosynthesis; synthesized by yeast; major B-vitamin by mass
Pyridoxine (B6)	20	5	60	mg/kg DCW	PLP cofactor for aminotransferases; synthesized by yeast
Folic A. (B9)	15	10	40	mg/kg DCW	One-carbon metabolism; synthesized by yeast; limiting in some defined media
Inositol	5000	3000	10000	mg/kg DCW	Phospholipid head group (PI); structural role in membranes; major component — often > 0.5% dry wt

Process Notes

Topic	Guidance
Biomass yield (Y_X/S)	0.40–0.55 g DCW/g sugar under aerobic conditions; lower under oxygen limitation. Theoretical max ~0.6 g/g for glucose.
Fed-batch strategy	Exponential feeding maintains µ below µ_max (~0.4 h⁻¹ for S. cerevisiae) to avoid Crabtree overflow. Target µ = 0.15–0.25 h⁻¹ for high biomass yield.
Nitrogen depletion	N is often the first limiting nutrient in fed-batch. Monitor NH₄⁺ online or via pH response. C:N ratio > 15–20 (by mass) leads to N limitation.
Phosphorus	P demand is highest during exponential growth (ATP, RNA synthesis). P:N ratio in medium ~1:7 mirrors biomass composition.
Magnesium	Mg²⁺ < 0.5 mM causes ribosome instability and growth inhibition. Often underestimated — ensure at least 1–2 mM in batch medium.
Trace element solutions	Prepare a 100–1000× concentrated stock in dilute HCl (pH 1–2) to prevent precipitation. Autoclave separately or filter-sterilise.
Vitamin stability	Thiamine, riboflavin, and folic acid are heat-labile and/or light-sensitive. Filter-sterilise (0.2 µm) and add post-autoclaving. Prepare fresh stocks weekly.
pH control	Optimal pH 4.5–5.5 for S. cerevisiae biomass production. Use NH₄OH or KOH for base, H₂SO₄ or H₃PO₄ for acid — these also serve as incidental N, K, S or P sources.
Dissolved oxygen	Maintain > 20–30% air saturation during aerobic fed-batch. Below 10% triggers partial anaerobiosis and ethanol accumulation (Crabtree effect).

Test against target: Biomass g DCW Y_X/S g/g

Compound	Salt / Note	Amount added (g)	Coverage	Max biomass (g DCW)

Enter compound amounts above to test the medium.