Production process of an alternative astaxanthin producer Chlamydomonas nivalis and investigation of its astaxanthin potential

Microalgae, which is the primary producer of natural astaxanthin, which is one of the most produced carotenoids in the industrial field, is a microorganism frequently used in energy, pharmaceutical, cosmeceutical, nutraceutical and waste water treatment fields thanks to its many other metabolites. In this thesis, it has been investigated that Chlamydomonas nivalis, which can live at low temperatures except cultivated species in temperate climate zone, can be used as an alternative producer of astaxanthin by cultivation in different stress conditions and photobioreactors. In order to determine the stress factors in the production of extremophilic green microalgae Chlamydomonas nivalis, which was purchased from UTEX culture collection as axenic, the cell number and density, dry weight, pH, temperature, photosynthetic activity, chlorophyll and carotenoid amounts in bubble column photobioreactors had analize with using different temperature, nutrient media and light intensities, and HPLC analysis was performed to determine the astaxanthin content. Effect of photobioreactor type to biomass production was investigated by scaled-up from small scale cultivation by petri and laboratory tubes to 5L of panel, tubular and stirred tank photobioreactors. Although no red cystic form was observed Chlamydomonas nivalis was able to tolerate temperatures up to 28°C and, astaxanthin production was determined highest as 0.137 mg/g in bubble column photobioreactor with content BBM nutrient medium.