I am attempting to culture Chlorella vulgaris in a laboratory setting. I am using a synthetic seawater solution with ~35% salinity along with an f/2 growth medium. Autoclaved. Light is on a 16:8 cycle at 60 mumol/m2/s. Mixing is at 60 RPM. Initial pH around 8.4. No air bubbling is used. Foam cap on erlenmeyer flasks in a hood. I have been measuring the OD at 600nm. This is the second sub-culture and the OD began at 0.60 and ended at 0.98 after 7 days. This seems to be a very slow growth rate. Based on the information I have given, does anyone have any advice for these cultures?
Yes, thank you, Jakub. 3.5% salinity is correct. It is made in the lab with NaCl, MgCl2, NaSO4, CaCl2, NaHCO3, KBr, HBrO3. Trace metals, vitamins, and NaNO3 and NaHPO4 according to Guillards f/2 formulation.
That seems to be w very low nutrient medium. Try Bristol or BG11 medium.
Seems indeed to grow very slowly. I recommend lowering initial pH to approx. 7.5 and to add air bubbling to increase CO2-supply. Also, increasing PFD to 100-150 umol/m2/s. Growth temperature? I would use 25C.
Hello, I'm working with the same sp. It is a fresh water microalgae. Try BBM -Fresh water medium. It is growing better in BBM than in f/2 medium. Optimum pH 7-9 range, 30 C temperature, 150 rpm continuous shaking, I am taking Abs readings at 750 nm wavelength to measure the growth.
Helo Brent,
Chlorella tends to prefer lower salinity than other species, use salinity of 10-15 ppt or equivalent. I think it's better to use Walne medium because Chlorella belongs to green algae, non diatoms.
Hello Brent,
Is there any other reason why sub culture is done after 7 days. Is not that already entering death phase ?. Also use light intensity at 1000 - 4000 lux or equivalent.
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