Culturing Daphnia food

Please cite as: Ebert, D. Web-guide to Daphnia parasites.

Chemostats

Chemostats for algae production

Green algae Scenedesmus

Green algae Scenedesmus

Scenedesmus in a counting chamber

Scendesmus in a counting chamber

We grow mainly the green algae Scenedesmus in chemostats. The chemostats have a capacity of about 2.5 liters and a flowthrough of 2 liters per day. We use the following medium, which is routinely produced by mixing 7 stock solutions with TES in deionized (or destilled) water. To produce 20 liter algae medium add to 20 liter water: 2.3 g TES and 20 ml of each of the 7 stock solutions A - G (in this order!). Afterwards we pump the entire medium through a 0.2 micro-meter filter to sterilize it. (Alternative sterilize in autoclave)

Stock solution Chemical Concentration [g/l]
A CaCl2× 2 H20 36.8
B MgSO4× 7 H2O 37.0
C NaHCO3 12.6
D K2HPO4× 3 H2O 11.4
E NaNO3 85.0
F Na2SiO3× 5 H2O 21.2
G* NaEDTA 4.360
FeCl3× 6 H2O 3.150
CuSO4× 5 H2O 0.010
ZnSO4× 7 H2O 0.022
CoCl2× 6 H2O 0.010
MnCl2× 4 H2O 0.180
Na2MoO4× 2 H2O 0.006
H3BO3 1.000

* Solution G contains among others, all the trace elements.

Some notes on how we run the chemostats:

  • We use LED, placed all around the chemostats (see pictures).
  • Keep the flow rate high, other wise bacteria take over.
  • We run several chemostats at a time and replace them after about 6 weeks. The algae quality decreases when the chemostats run for much longer.
  • We measure the CO2 concentration in the chemostats and when the pH goes up, we add CO2 to the air. This brings the pH back down. We try to keep the pH between 7 and 7.8. Since we do this, we multiplied the algae production.
Chemostats and feeding bottles

Full set of chemostats for algae mass production

Chemostats and feeding bottles

Chemostats with CO2 controller at the right

Chemostats and feeding bottles

Details of chemostats for algae production