When a culture from a culture collection arrives or is collected from outside waters/soils, it should be cultivated in small volumes before it can be used as inoculum for photobioreactors. This can be done in a light climate cabinet under continuous light or light with a day/night rhythm of 16h/8h. Cultures are grown at a set temperature (20-37°C) and with a low light intensity (50-100 umol m^-2s^-1). They are orbital shaken (100 r.p.m.) to keep the microalgae into suspension. Air is enriched with 2% carbon dioxide and is blown into the headspace to keep the pH constant and to ensure that there is sufficient carbon available for the microalgae.
After sufficient growth (depending on species: growth 1-6 weeks), the culture inside the flasks can be used as inoculum for photobioreactors.

Shake flask cultivation in a closed incubator