硫酸铵盐析条件对多管藻R-藻红蛋白和R-藻蓝蛋白得率和纯度的影响

 藻胆蛋白是一类用途广泛、市场前景广阔的天然色素蛋白，但分离纯化困难。粗提条件优化对最终获得的藻胆蛋白的得率和纯度影响较大。研究了硫酸铵饱和度、盐析次数、分级盐析对海洋红藻多管藻R-藻红蛋白（RPE）和R-藻蓝蛋白（RPC）提取得率和纯度的影响。结果表明，多管藻RPE和RPC的得率随硫酸铵饱和度的提高而增加，饱和度为60%时得率最高，分别为91.59%、97.98%。饱和度20%的硫酸铵仍能沉淀47.3%的RPE和24.8%的RPC。RPE的纯度随硫酸铵饱和度的提高而降低，但RPC纯度随硫酸铵饱和度的提高而增加，至饱和度为45%时纯度最高，之后随饱和度的提高而缓慢降低。饱和度<40%时，RPE/RPC得率比随硫酸铵饱和度提高而增加；饱和度>40%时，RPE/RPC得率比趋于稳定。硫酸铵盐析2次与盐析1次相比，RPE、RPC的得率降低，但纯度提高。二步法盐析比一步法盐析RPE、RPC的纯度分别提高122.42%、18.67%，但得率降低。因此硫酸铵盐析提取多管藻RPE、RPC时，以饱和度60%为宜，盐析2次，二步法盐析有利于藻胆蛋白纯度的提高，二步法盐析时初次使用的硫酸铵饱和度应<20%。藻胆蛋白盐析条件优化可为藻胆蛋白的进一步分离纯化奠定基础。

Purification and Recovery of R-phycoerythrin and R-phycocyanin from Polysiphonia urceolata under Different Ammonium Sulfate Precipitation Conditions

Phycobiliproteins are a family of natural pigment proteins with wide applications and promising market prospects, but their extraction and purification is difficult. Extraction optimization plays an important role in the recovery and purification of the final phycobiliproteins. In this paper, ammonium sulfate saturation, precipitation frequency, ammonium sulfate fractionation are employed to extract R-phycoerythrin and R-phycocyanin from marine red alga Polysiphonia urceolata. The results show that the yields of RPE and RPC are increased with increasing ammonium sulfate saturation. At 60% saturation, their yields reach the highest, up to 91.59% and 97.98%, respectively. 20% saturation could still precipitate 47.3% of RPE and 24.8% of RPC. The purity of RPE is decreased with increasing salt concentration. However, RPC purity is increased with increasing ammonium sulfate saturation, at 45% saturation, the purity reaches the highest, and then slowly decreases as the saturation further increases. During the saturation of 20%~40%, the recovery ratio of RPE and RPC increases with increasing salt concentration; at 40%, the ratio reaches the highest, then is stabilized above 40%. The twice ammonium sulfate precipitation is better than once for RPE and RPC extraction, their yields fall, but their purity is increased. Ammonium sulfate fractionation could significantly increase the purity of RPE and RPC, by 122.42% and 18.67%, as compared to one-step salting, but their yield is decreased significantly. So 60% saturation of ammonium sulfate is suitable for extraction of RPE and RPC from Polysiphonia urceolata, twice salting and two-step fractionation are good for purity increasing, but the first fractionation saturation of ammonium sulfate should be below 20%. This study can be a help for the phycobiliproteins purification.