Effect Of5-aminolevulinic Acid On Algae Growth And Product Accumulation

As a growth regulator,5-aminolevulinic aicd (ALA) was widely used in plants cultivation. However, there were few reports about the application of ALA in algae cultivation. Using Chlorella and Haematococcus pluvilalis as experimental material, this work mainly focused on the effects of5-aminolevulinic aicd on algea growth and product accumulation, which was the foundation of ALA application in algae cultivation. The main results are shown as follows:1) Optimized culture medium for Chlorella growth and lipid accumulation was received, by examing the dry cell weight and total lipid concentration of Chlorella pyrenoidosa FACHB-9under various culture conditions. The ultimate medium, which was named Mf2medium, contained (per liter):NaHCO31000mg, KNO3100mg, urea120mg, MgSO4·7H2O20mg, CaCl2·2H2O25mg, NaCl1000mg, KH2PO42620mg, K2HPO4·3H2O7020mg, H3BO32.86mg, Co(NO3)2·6H2O0.05mg, MnCl2·4H2O1.86mg, ZnSO4·7H2O0.22mg, CuSO4·5H2O0.08mg, FeC6H5O76mg, Na2MoO4·2H2O0.39mg, Vitamin B10.1mg, Vitamin B120.0005mg, Biotin0.5mg, and5%(v/v) CO2injected in. By using this medium, the dry cell weight and total lipid concentration of Chlorella reached as high as1.32g·L-1and0.270g·L-1, respectively.2) The addition of exogenous ALA promoted Chlorella growth, thereby enhanced lipid concentration indirectly. The relationship between Chlorell dry cell weight and ALA concentrations was shown as an M-shaped curve. The optimized ALA adding scheme was adding2.98μM ALA every5-10days. Under this condition, the dry cell weight and total lipid concentration of Chlorella reached as hight as1.65g·L-1and0.328g·L-1, respectively.3) Optimized the culture medium for Haematococcus pluvilalis growth and astaxanthin accumulation was received, by examing the dry cell weight and astaxanthin content of Haematococcus pluvilalis FACHB-712under various culture conditions. The ultimate medium, which was named MOHM medium, contained (per liter):NaHCO3400mg, KNO3410mg, MgSO4·7H2O123mg, CaCl2·2H2O55mg, KH2PO432.7mg, K2HPO4·3H2O858mg, CoCl2·6H2O0.011mg, MnCl2·4H2O0.98mg, CuSO4·5H2O0.012mg, FeC6H5O72.62mg, Na2MoO4·2H2O0.12mg, Cr2O30.75mg, Vitamin B10.0175mg, Vitamin B120.015mg, Biotin0.025mg. By using this medium, the dry cell weight and astaxanthin content of Haematococcus pluvilalis reached as high as0.49g·L-1and6.45mg·L-1, respectively.4) The addition of exogenous ALA promoted Haematococcus pluvilalis growth, howere, restrained astaxanthin accumulation. The relationship between dry cell weight of Haematococcus pluvilalis and ALA concentrations was shown as an M-shaped curve. The optimized ALA adding scheme for Haematococcus pluvilalis growth and astaxanthin accumulation was adding1.79μM ALA every5-10days. Under this condition, the dry cell weight and astaxanthin content of Haematococcus pluvilalis reached as high as0.54g·L-1and6.93mg·L-1, respectively.