n_20_medium

CultureMech:000183 algae COMPLEX LIQUID
Original name: N/20 Medium

Overview

External ontology
UTEX:n-over-20-medium (source link unavailable) — N/20 Medium
Applications
  • Algae cultivation
  • Phytoplankton culture
  • Microalgae research
Notes
UTEX prepares N/20 Medium from a defined freshwater salt and acetate base with P-IV Metal Solution, Vitamin B12, and Thiamine Vitamin Solution added at source-stated volumes.

Composition

flowchart LR
    CultureMech_000183["n_20_medium"]
    ing0_dH2O["dH2O"]
    CultureMech_000183 --> ing0_dH2O
    CHEBI_15377["CHEBI:15377"]
    ing0_dH2O -.-> CHEBI_15377
    ing1_KH2PO4["KH2PO4"]
    CultureMech_000183 --> ing1_KH2PO4
    CHEBI_63036["CHEBI:63036"]
    ing1_KH2PO4 -.-> CHEBI_63036
    ing2_NaNO3["NaNO3"]
    CultureMech_000183 --> ing2_NaNO3
    CHEBI_63005["CHEBI:63005"]
    ing2_NaNO3 -.-> CHEBI_63005
    ing3_K2HPO4["K2HPO4"]
    CultureMech_000183 --> ing3_K2HPO4
    CHEBI_131527["CHEBI:131527"]
    ing3_K2HPO4 -.-> CHEBI_131527
    ing4_NaCl["NaCl"]
    CultureMech_000183 --> ing4_NaCl
    CHEBI_26710["CHEBI:26710"]
    ing4_NaCl -.-> CHEBI_26710
    ing5_CaCl2_x_2_H2O["CaCl2 x 2 H2O"]
    CultureMech_000183 --> ing5_CaCl2_x_2_H2O
    CHEBI_86158["CHEBI:86158"]
    ing5_CaCl2_x_2_H2O -.-> CHEBI_86158
    ing6_MgSO4_x_7_H2O["MgSO4 x 7 H2O"]
    CultureMech_000183 --> ing6_MgSO4_x_7_H2O
    CHEBI_31795["CHEBI:31795"]
    ing6_MgSO4_x_7_H2O -.-> CHEBI_31795
    ing7_Sodium_acetate["Sodium acetate"]
    CultureMech_000183 --> ing7_Sodium_acetate
    CHEBI_32954["CHEBI:32954"]
    ing7_Sodium_acetate -.-> CHEBI_32954
    ing8_TES_buffer["TES buffer"]
    CultureMech_000183 --> ing8_TES_buffer
    CHEBI_39035["CHEBI:39035"]
    ing8_TES_buffer -.-> CHEBI_39035

Ingredients (9)

# Ingredient Concentration Ontology Notes
1 dH2O
H2O 18.015 g/mol
1000 ML_PER_L CHEBI:15377
water
 UTEX starts N/20 Medium with approximately 850 mL dH2O.
2 KH2PO4
H2O4P.K 136.084 g/mol
Sigma P 0662
1.29 MILLIMOLAR CHEBI:63036
potassium dihydrogen phosphate
 UTEX adds 2 mL/L of a 17.5 g/200 mL dH2O stock, for 1.29 mM final.
3 NaNO3
NO3.Na 84.994 g/mol
Fisher BP360-500
0.14 MILLIMOLAR CHEBI:63005
sodium nitrate
 UTEX adds 100 uL/L of a 25 g/200 mL dH2O stock, for 0.14 mM final.
4 K2HPO4
HO4P.2K 174.174 g/mol
Sigma P 3786
0.43 MILLIMOLAR CHEBI:131527
dipotassium hydrogen phosphate
 UTEX adds 1 mL/L of a 15 g/200 mL dH2O stock, for 0.43 mM final.
5 NaCl
Cl.Na 58.443 g/mol
Fisher S271-500
0.43 MILLIMOLAR CHEBI:26710
sodium chloride
 UTEX adds 1 mL/L of a 5 g/200 mL dH2O stock, for 0.43 mM final.
6 CaCl2 x 2 H2O
Ca.2Cl.2H2O 147.014 g/mol
Sigma C-3881
0.17 MILLIMOLAR CHEBI:86158
calcium chloride dihydrate
 UTEX adds 1 mL/L of a 5 g/200 mL dH2O stock, for 0.17 mM final.
7 MgSO4 x 7 H2O
7H2O.Mg.O4S 246.473 g/mol
Sigma 230391
0.3 MILLIMOLAR CHEBI:31795
magnesium sulfate heptahydrate
 UTEX adds 1 mL/L of a 15 g/200 mL dH2O stock, for 0.3 mM final.
8 Sodium acetate
C2H3O2.Na 82.034 g/mol
Fisher BP 333
8.12 MILLIMOLAR CHEBI:32954
sodium acetate
 UTEX lists 0.67 g/L Sodium acetate, for 8.12 mM final.
9 TES buffer
Sigma T 1375
4.01 MILLIMOLAR CHEBI:39035
TES
 UTEX lists 0.92 g/L TES buffer, for 4.01 mM final.

Preparation

  1. To approximately 850 mL dH2O, add each component except Vitamin B12 and Thiamine Vitamin Solution in the UTEX order while stirring continuously.
  2. Bring total volume to 1 L with dH2O.
  3. Cover and autoclave medium.
  4. Cool the autoclaved medium.
  5. Add Vitamin B12 and Thiamine Vitamin Solution.
  6. Store at refrigerator temperature.

Solutions

P-IV Metal Solution

Dose: 6 ML_PER_L

Stock composition
IngredientConcentrationNotes
dH2O 1000 ML_PER_L UTEX brings P-IV Metal Solution to 1 L with dH2O.
Na2EDTA x 2 H2O 0.75 G_PER_L UTEX lists 0.75 g/L Na2EDTA x 2 H2O, 2 mM final, and dissolves it fully before the other P-IV components.
FeCl3 x 6 H2O 0.097 G_PER_L UTEX lists 0.097 g/L FeCl3 x 6 H2O, for 0.36 mM final.
MnCl2 x 4 H2O 0.041 G_PER_L UTEX lists 0.041 g/L MnCl2 x 4 H2O, for 0.21 mM final.
ZnCl2 0.005 G_PER_L UTEX lists 0.005 g/L ZnCl2, for 0.037 mM final.
CoCl2 x 6 H2O 0.002 G_PER_L UTEX lists 0.002 g/L CoCl2 x 6 H2O, for 0.0084 mM final.
Na2MoO4 x 2 H2O 0.004 G_PER_L UTEX lists 0.004 g/L Na2MoO4 x 2 H2O, for 0.017 mM final.
UTEX adds 6 mL P-IV Metal Solution per liter.

Vitamin B12

Dose: 1 ML_PER_L

Stock composition
IngredientConcentrationNotes
dH2O 1000 ML_PER_L UTEX prepares the Vitamin B12 stock in 200 mL HEPES buffer.
HEPES buffer pH 7.8 12 G_PER_L Converted from 2.4 g/200 mL in the UTEX Vitamin B12 stock.
Vitamin B12 0.135 G_PER_L Converted from 0.027 g/200 mL in the UTEX Vitamin B12 stock.
UTEX adds 1 mL Vitamin B12 stock per liter.

Thiamine Vitamin Solution

Dose: 1 ML_PER_L

Stock composition
IngredientConcentrationNotes
dH2O 1000 ML_PER_L UTEX prepares the thiamine stock in 200 mL HEPES buffer.
HEPES buffer pH 7.8 12 G_PER_L Converted from 2.4 g/200 mL in the UTEX thiamine stock.
Thiamine 0.335 G_PER_L Converted from 0.067 g/200 mL in the UTEX thiamine stock.
UTEX adds 1 mL Thiamine Vitamin Solution per liter.

Target organisms

No target organisms are recorded.

Provenance

TimestampCuratorActionNotes
2026-01-28T00:00:00+00:00 utex-import Imported from UTEX Culture Collection Source ID: n-over-20-medium, URL: https://utex.org/products/n-over-20-medium
2026-03-13T06:18:53.470847Z culturemech-id-assigner-v1.0 Assigned CultureMech ID Assigned stable identifier: CultureMech:000183
2026-03-17T19:45:04.400712+00:00 normalize_media_names_to_snake_case.py NAME_NORMALIZED Normalized name from "N/20 Medium" to "n_20_medium" for consistent matching
2026-05-16T09:02:56.068950+00:00 migrate_legacy_fields.py MIGRATED_LEGACY_FIELDS curation_history.date->timestamp=1; references.reference_id->reference=2; category->lowercase=1
2026-05-16T09:11:01.277954+00:00 migrate_preparation_steps.py MIGRATED_PREPARATION_STEPS instruction->action+description for 9 step(s)
2026-08-30T00:58:30.903976+00:00 repair_utex_ingredients.py REPAIRED_UTEX_COMPOSITION Restored 11 ingredient name(s) and amount(s) from a re-fetched UTEX capture. The original fetcher read fixed column positions, so the row ordinal was stored as the ingredient name, the component name as the amount, and the Amount column was never read; concentration was then filled in as G_PER_L regardless. Source: https://utex.org/pages/algal-culture-media, captured 2026-08-29T17:46:40.207779.
2026-09-06T00:00:00-07:00 repair_utex_n20_snow_score35.py RESOLVED_UTEX_N20_SNOW_SCORE35 UTEX prepares N/20 Medium from a defined freshwater salt and acetate base with P-IV Metal Solution, Vitamin B12, and Thiamine Vitamin Solution added at source-stated volumes.