Modified Desmidiacean Medium
The final medium is prepared on a tube by tube basis, using 15 mL glass tubes, stoppered with rubber-lined screw caps.
Directions
For 1 L Total
- To approximately 900 mL of dH2O add the first 7 components in the order specified while stirring continuously.
- Bring total volume to 1 L with dH2O.
- Cover and autoclave medium.
- Allow to cool.
- Add 1 sterile barley grain per test tube then store at refrigerator temperature.
| # | Component | Amount | Stock Solution Concentration | Final Concentration |
|---|---|---|---|---|
| 1 | KNO3 (Baker 3190) |
10 mL/L | 1 g/100 mL | 0.9 mM |
| 2 | (NH4)2HPO4 (Fisher A686) |
5 mL/L | 0.2 g/100 mL | 0.075 mM |
| 3 | MgSO4•7H2O (Sigma 230391) |
10 mL/L | 0.1 g/100 mL | 3.3 µM |
| 4 | CaSO4•2H2O saturated solution (Mallinckroft 4300) |
10 mL/L | ||
| 5 | Soilwater: GR+ Medium | 20 mL/L | ||
| 6 | Soilwater: Peat Medium | 10 mL/L | ||
| 7 | MWC Metal Solution | 5 mL/L | ||
| 8 | Barley grains autoclaved | 1 grain/10 mL |
Important Notes To Consider:
- The quality of water, including natural seawater, is important. The term 'dH2O' generally refers to distilled, deionized, distilled/deionized water, Milli-Q water (Millipore Corp.), etc. Natural seawater and natural freshwater should be obtained from a non-polluted source.
- When dissolving chemicals, wait for the first component to dissolve before adding the second. Stirring, and sometimes the addition of heat, is often required to dissolve the chemicals efficiently. Preparation of stock solutions for frequently made algal culture media make preparing media convenient but also necessary to avoid errors from weighing very tiny amounts.
- Attention should be given to the pH of the final medium. In most cases, if pH adjustment is required, this occurs before sterilization. Please note that autoclaving removes carbon dioxide from media lacking carbonate stabilizing buffers. This would make the medium very alkaline soon after removal from the autoclave. In these cases, you should wait approximately 24 hours for gaseous equilibrium before inoculating the medium.
Additional algal culture media recipes can be found at the following other major Collections' websites:
- Culture Collection of Algae and Protozoa (CCAP)
- National Center for Marine Algae and Microbiota (NCMA)
- National Institute for Environmental Studies (NIES) Microbial Culture Collection
- The Pasteur Culture Collection of Cyanobacteria (PCC)
- The Culture Collection of Algae at Goettingen University (SAG)
- Canadian Phycological Culture Centre (CPCC)
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