The Extraction Of Phycocyanin From Cyanobacteria In Lake Chaohu

Along with the intensification of the degree of eutrophication in recent years, this paper by chaohu fresh algae bloom as the research object, by freezing and thawing and salting-out with ammonium sulfate gradient method combining the aqueous two-phase extraction of cyanobacteria cells algal blue protein, by algal blue protein as an index, the purity and yield of algal blue protein stability were studied. The results showed that the repeated freeze-thaw 2-3 times and 4 steps salting-out method combined with the aqueous two-phase extraction and the best extraction effect can be obtained.Taking repeated freeze-thaw cycles, the gradient moisture content, the different medium of freezing and thawing experiment were compared based on the phycocyanin purity value and recovery. The result showed that the optional medium is PBS buffer solution.the concentration is 0.0025mol/L, and the moisture content of blue alga from 96% to 97.5% is better than others, so is recommended as a common standard for phycocyanin extraction from blooms water samples in Lake Chaohu.In this paper, salting-out are employed to extract the phycocyanin from fresh blue algae, and stability of phycocyanin was studied. An approach, which include freezing and thawing blue algae three times in water, and use golden section method to select the appropriate amount of ammonium sulfate in the range of 0 to 70percent, based on the phycocyanin purity value and recovery. Results showed that the purity up to 3.157 with a recovery of 1.664% is engendered by salting-out of ammonium sulfate saturation respectively 21%,30.4%,26.28% and 47.76%, and then put blue alga protein in 12 h 100000 daltons dialysis bag dialysis, the purity can be improved to 3.60.In aqueous two-phase extraction experiments, with blue alga protein purity and yield as index, to get algal blue protein liquid through freezing and thawing and salting out. And then study two aqueous two-phase extraction and the effects of different conditions on algal blue protein extraction. The result shows that due to limited experiment time and simplified the operation steps, if each first extraction choose 1000 molecular weight polyethylene glycol (peg) and its concentration should be 10%, ammonium sulfate’s mass concentration should be 15%, requires 2 hours; In the second extraction, should choose the polyethylene glycol (peg) within 10% concentration, ammonium sulfate’s mass concentration should be 20%, also requires 2 hours.In this paper, effects of various parameters such as beam, time, pH, temperature, ethanol and some common food additives on phycocyanin stability were studied. Results showed that phycocyanin is steady in dark and under 30℃, and it is also steady on condition of neutral pH value. Beyond the range of its stability decreased, adding ethanol and citric acid will lead to a decline in the stability of the phycocyanin, and sodium chloride and sodium benzoate on the stability of the phycocyanin less influence.