Effects of temperature,illumination and salinity on astaxanthin accumulation in Haematococcus pluvialis aberrant species

Astaxanthin,a kind of secondary carotenoid,is widely used in health care and feed industry for its hyperploid antioxidative and good colouration.Its enormous market potential wins the unicellular green alga Heamatococcus pluvialis extensive attention from algologists home and abroad.H.pluvialis is the microalga being that claims the highest astaxanthin content.Researches on it have lasted a few decades.However,most of those researches were concentrated on basic cultivation and causation of astaxanthin accumulation.In H.pluvialis industry,how cultivation condtions affect the astaxanthin accumulation of H.pluvialis takes up a significant place.A great number of algologists have applied themselves to this question but have arrived at no universal answer.So the author of this thesis takes into consideration temperature,illumination and salinity,the effects of which on the astaxanthin accumulation have been studied. Haematococcus pluvialis aberrant species No.1 was cultivated in the MAV medium.The influence of the physical factors(temperature,illumination and salinity) on the astaxanthin accumulation was analysed.First,these experiments were carried out separately as three single factor tests when five grades(15?℃,(20?℃),25?℃,30?℃ and 35?℃) of the temperature,six grades(0,1?000?lx,2?000?lx,4?000?lx,6?000?lx and 8?000?lx) of the illumination and six grades(0,4,8,12,16 and 20) of salinities were set.The results showed that: the best conditions for the growth of the algae was 15-20?℃,1?000-2?000?lx of the illumination and 0 of the salinity,while the most excellent conditions respectively for the astaxanthin accumulation was that when the temperature ranged from 25?℃ to 30?℃,and illumination was 8?000?lx and the salinity ranged from 4 to 8.Then an interaction test between the temperature and the salinity was carried out,and each factor was set with three levels.The illumination was 6?000?lx,8?000?lx and 10?000?lx while the salinity was 4,8 and 12.The final results indicated that 8?000?lx of the illumination interacted with 8 of the salinity was the most excellent conditions for the astaxanthin accumulation.