Dept. of Food Science, College of Agriculture and Life Sciences, Cornell Univ., Ithaca, NY, 14853, U.S.A.
Dipartimento di Scienze degli Alimenti e del Farmaco, Parco Area delle Scienze 47/A, 43124, Parma, Italy.
J Food Sci. 2020 Mar;85(3):727-735. doi: 10.1111/1750-3841.14842. Epub 2020 Jan 30.
Phycocyanin, a natural blue colorant, is typically extracted from liquid biomass of Arthrospira platensis, a blue-green algae called spirulina. In this study, we developed a scalable process to extract phycocyanin from dried spirulina biomass. First, we established the optimal ionic strength and pH for the extraction buffer. The results showed that a minimum ionic strength (>5 g/L NaCl) must be maintained to minimize the co-extraction of the green chlorophyll. The optimal pH of the phosphate buffer (100 mM) for phycocyanin extraction is 7.5; however, the pH should be immediately adjusted to 6.0 to 6.5 after the extraction to keep phycocyanin stable. Second, we also investigated three processing techniques, that is, high-pressure processing (HPP), pulsed electric field (PEF), and ultrasonication, to break the cell walls of spirulina and facilitate the release of phycocyanins into extraction buffers. HPP and PEF do not lead to the release of phycocyanin into the extraction buffer. However, ultrasonication breaks down the spirulina into fine particles and releases most of the phycocyanin, along with other impurities, immediately after the treatment. Last, it has been revealed that most of the phycocyanin can be extracted from biomass within 3 hr by phosphate buffer only (pH 7.5, 100 mM) at room temperature. It is concluded that there is no need to treat the rehydrated biomass solution by HPP, PEF, or ultrasonication due to the minimal benefits they brought for the extraction. Based on these results, we proposed an extraction process for the plant production of phycocyanin starting from dried spirulina biomass. PRACTICAL APPLICATIONS: Limited information can be found on the extraction of phycocyanin from dried spirulina biomass, especially how to better preserve the natural blue color of phycocyanin during extraction. We have investigated the method and presented a different view from previous processes. Pulsed electric field, high-pressure processing, and ultrasonication were employed to accelerate the extraction of phycocyanin from dried biomass. However, it was found that, unlike the extraction from live wet biomass, these techniques do not help with the extraction from dried biomass. Based on investigations, we have proposed a process that can be easily scaled up for the commercial production of phycocyanin from dried spirulina biomass.
藻蓝蛋白是一种天然蓝色着色剂，通常从蓝绿藻螺旋藻的液态生物质中提取。在这项研究中，我们开发了一种从干燥螺旋藻生物质中提取藻蓝蛋白的可扩展工艺。首先，我们确定了提取缓冲液的最佳离子强度和 pH 值。结果表明，必须保持最小离子强度（>5 g/L NaCl）以最小化绿色叶绿素的共提取。提取藻蓝蛋白的磷酸盐缓冲液（100 mM）的最佳 pH 值为 7.5；然而，提取后应立即将 pH 值调整至 6.0 至 6.5，以保持藻蓝蛋白的稳定性。其次，我们还研究了三种加工技术，即高压处理（HPP）、脉冲电场（PEF）和超声处理，以打破螺旋藻的细胞壁，促进藻蓝蛋白释放到提取缓冲液中。HPP 和 PEF 不会导致藻蓝蛋白释放到提取缓冲液中。然而，超声处理会将螺旋藻破碎成细小颗粒，并在处理后立即将大部分藻蓝蛋白和其他杂质释放到提取缓冲液中。最后，结果表明，仅用磷酸盐缓冲液（pH 7.5，100 mM）在室温下 3 小时内即可从生物质中提取大部分藻蓝蛋白。因此，由于 HPP、PEF 或超声处理带来的益处有限，无需对再水合的生物质溶液进行处理。基于这些结果，我们提出了一种从干燥螺旋藻生物质中提取藻蓝蛋白的提取工艺。实际应用：从干燥的螺旋藻生物质中提取藻蓝蛋白的方法信息有限，特别是在提取过程中如何更好地保持藻蓝蛋白的天然蓝色。我们已经研究了这种方法，并提出了与以前工艺不同的观点。脉冲电场、高压处理和超声处理被用于加速从干燥生物质中提取藻蓝蛋白。然而，与从活体湿生物质的提取不同，这些技术在从干燥生物质的提取中并没有帮助。基于调查，我们提出了一种可以很容易地扩展到从干燥螺旋藻生物质中商业生产藻蓝蛋白的工艺。
