Algae Media

The most important aspects in algae growing conditions are nutrient quantity and quality, light, pH, turbulence, salinity and temperature. Concentrations of algae in media are generally much higher than those found in nature, so the media or culture must be enriched with nutrients to boost the seawater in order to support these higher cell densities.

The table below shows a generalised set of conditions for culturing algae

Algae don’t need equal amounts of every nutrient, so they are mixed at different ratios. Seawater will by itself supply the necessary nutrients for limited growth of some marine species. However, most media recipes supply nutrients vastly in excess of the concentrations normally found in order to support high biomass cultures. Different species require different amounts of some nutrients.

Once you have selected your algae strain, you will require a matched growing medium. An example is provided below from the CSIRO Media Recipes.

Medium f (and fE) – CSIRO Modification

This medium is a slight modification of the original f medium of Guillard and Ryther (1962). It is most commonly prepared at half strength where it is designated as f2 or f/2.

Reference: Jeffrey, S. W. and LeRoi, J.-M. (1997). Simple procedures for growing SCOR reference microalgal cultures. In: S.W. Jeffrey, R.F.C. Mantoura and S.W. Wright (Eds) Phytoplankton pigments in oceanography; Monographs on oceanographic methodology 10, UNESCO, France, pp 181-205.

Guillard, R. R. L. and Ryther, J. H. (1962) Canad. J. Microbiol., 8: 229-239.

Preparation Methods

1. To Prepare Medium f

Add 1 mL of each stock solution (1 – 5) to 1 litre seawater. Dispense to flasks and autoclave at 121°C (15PSI, 15 mins).

Phosphate (see Stock 6.- NaH2PO4.2H2O ). This must be sterilised separately from seawater to prevent precipitation.  Dilute original phosphate stock with distilled water such that 1 mL added to each flask of sterile medium will give the required concentration of phosphate in the medium. Autoclave dilute phosphate stock at 121°C (15PSI, 15 mins). After cooling, dispense aseptically with sterilised automatic dispenser.

For example: For 100 x 125 mL Erlenmeyer flasks, each containing 75 mL medium, prepare dilute phosphate stock as follows:

f and fE media:

Take 7.5 mL of original phosphate stock and make up to 100 mL with distilled water.

Pour into a 250 mL Schott bottle and autoclave to sterilize. Dispense 1 mL per flask aseptically.

f2 and fE2 media:

Take 3.75 mL of original phosphate stock and make up to 100 mL with distilled water.

Pour into a 250 mL Schott bottle and autoclave to sterilize. Dispense 1 mL per flask asepically.

Scale up in the same proportion for larger volumes.

To Prepare Medium fE

Prepare as medium f, but also add 1 mL of Na2EDTA.2H2O stock solution (7).

To Prepare Medium f2

Prepare as medium f, but using 0.5 mL of each stock solution instead of 1.0 mL of each.

To Prepare Medium fE2

Prepare as medium f2, but also add 0.5mL of Na2EDTA.2H2O stock solution.

2. To Prepare Medium f2 concentrated nutrients

Take 5mL of each stock solution (1 – 6) and make up to 100 mL with distilled water.

Pour into a 250 mL Schott bottle.

Autoclave at 121°C (15PSI, 15 mins).

Alternatively, filter sterilise using a 0.22 mm filter into a sterile 250 mL Schott bottle.

Use 1 mL per 100 mL sterile seawater adding correct amount of nutrient aseptically.

go from Algae Media back to Photobioreactors