Research On Culture Condition And Enhancing Bioactive Content Of Porphyridium Cruentum

On the basis of detailed study of Porphyridium Cruentum, the optimal culture medium is obtained and the biomass of P. cruentum are increased. The extraction and purification of PE and PUFA of P. cruentum are studied, under the optimal conditions the bioactive compounds productivity can be increased effectively.P. cruentum cells grow very slowly in the natural and artificial seawater medium, and the biomass density is also lower. The major nutrition of P. cruentum is optimized by the methods of single factor and uniform design. The results show that carbonaceous, nitrogen, phosphor and VB2 have obvious affect on the growth, however, VB1 and Fe-EDTA had no evident affect on the growth of those cells; On the base of the above, a steady and high yield medium is obtained as NaHCO3 2.755g/L, NaNO3 3.224g/L, KH2PO40.035g/L, VB12 2.772μg/L, VB1 0.9mg/L and Fe-EDTA 0.11mg/L.There are many bioactive compounds in this microalgal cells such as phycoerythrin, EPA, DHA etc., therefore, the cell fragmentation degree has direct affect on the extract efficiency of those bioactive compounds. The research results show that the production of phycobiliproteins can be increased with improvement of crushing rate. When crushing efficiency is 71%, the content of phycoerythrin is 50.2%, however, when it is 31%, the content of phycoerythrin only reach to 21.2%. Compared with the method of freezing and thawing, the ultrasonic method has higher crushing efficiency. When duty cycle, output power and crushing time respectively are 50%, 150W and 20 minutes, the cell fragmentation efficiency arrives to 87.4%.The character, extraction and purification methods of the B-PE are studied. The results show that the B-PE can be separated effectively on the column of HA and its purity arrives at 4.32. Our researches note that some environmental factors such aslight quality, light density and salts can affect the content of B-PE. The content of proteins and B-PE can be reached to 24.56% and 9.14% under the culture condition by green light, and the content of B-PE also can is increased with the increasing light density.The environment factors such as cultivation time, light intension,aeration and pH can affect the synthesis of fatty acids. The results manifest that aeration and the optimal pH enhance the content of PUFA. In logarithm growth phase, the total fatty acids content of P. cruentum reaches its maximum value(12.84% in dry cell mass), in which the content of AA is 20.65%, and EPA is about 25%. Light density can improve the accumulate of total fatty acids. When light intension is 35001x, the total fatty content account for 12.84% (in dry cell mass), which is 1.48 times than the light density 18001x. When light intension increased to 54001x, the content of total fatty is steady.