Team:ECUST China/Description
The understanding of phycocyanin began with food pigment. In the investigation of the current situation of pigment market and consumer survey, we found that the consumer concern in relation to health and safety issues about the use of synthetic colorants in foods has increased in recent years . The Food and Drug Administration (FDA) in USA, the European Food Safety Authority (EFSA) in Europe, and many other national authorities around the world have restricted the use of synthetic colorants in foods, confectionery and beverages because of their confirmed or suspected association with increased cancer development or induction of allergic reactions. For the same reasons other colorants are under study and are only provisionally allowed. The tendency in food manufacturers is therefore going progressively toward the use of natural additives. Among the different colors, the confectionary and drinks industry has a high demand in blue colorants, however, they are uncommon in nature thus leading to the use of synthetic ones. For this reason the food industry is now expressing a growing interest in the search, use, and stabilization of natural blue colorants.[1]
As one of the rare pigment proteins in nature, phycocyanin is not only bright in color, but also a nutrient rich protein. It has complete amino acid composition and high content of essential amino acids, accounting for 37.2% of the total amino acid content. It has the reputation of food diamond. Beyond its nutritional value, phycocyanin resulted to be antioxidant both in in vitro and in in vivo studies (in experimental animals), it is suggested to have anti-inflammatory, anti-viral and anti-cancer properties, and is reported to possess the capacity to stimulate the immune defence system[2], [3], [4], [5]. Moreover, phycocyanin is used as biochemical tracer in immunoassays due to its fluorescent properties[6], [7]. The commercial value for phycocyanin applications is around 60 million US$ per year and the current CAGR is about 15.35%.
In related investigations, we found that the current traditional method of producing phycocyanin is extracted from spirulina by physical and chemical methods. The extraction time and purity are the difficulties of technological extraction, leading to higher production costs of phycocyanin. In addition, the three wastes produced in the process are also a problem. We at ECUST_China2021 began to think about whether we can use green and efficient biological production methods to reduce its costs.
In the subsequent exchanges with several phycocyanin-producing companies, we learned that the stability of phycocyanin is low, which not only limits the production of phycocyanin, but also restricts its industrial application. In merchant surveys, merchants also reported that the instability of phycocyanin limits its processing and storage. Although phycocyanin is already used as a blue colorant in some foods and beverages, the phycocyanin is unstable to heat. At a temperature higher than 40-50°C, its degradation rate will greatly increase[8], preventing its use in those food products requiring high temperature processes, such as cooking or sterilization.
Fig. Effect of temperature on phycocyanin extract (PC-E) stability expressed in remaining concentration of PC (RCPC). (a) PC-E in sodium phosphate buffer (pH 6.0) was incubated for 75 min at different temperatures. (b) PC-E (0.5, 2.75, 5 mg mL−1) was incubated at 60 °C and RCPC was determined from 0 to 120 min at 15-min intervals. The non-heated PC-E was considered as control (100%). Data shown is the mean ± SD, n = 3.
In order to solve the above problems and expand the application range of phycocyanin, we finally chose to use synthetic biology methods to provide a brand new solution——We created a yeast magician and let it learn blue magic.
Through the literature, we found that phycocyanin from heat-resistant cyanobacteria PCC6715, its Tm=95±1℃. We choose this algae as a genetic source, for the choice of chassis organisms, we choose brewing yeast ——Saccharomyces cerevisiae S288C as chassis organisms. Yeast belongs to a simple single-cell eukaryotic organisms, easy to culture, and grow rapidly. Besides yeast itself is rich in nutrition, it contains a variety of proteins, eight essential amino acids, and rich in a variety of B vitamins, so it is a good nutrition. Binding yeast to phycocyanin can achieve the effect of 1+1 >2.
We have built two plasmids and inserted two modified plasmids into yeast, and eventually produced phycocyanin in the cytoplasm to make yeast blue. We used a complex regulatory network system and a method of targeted mutation to increase the expression of phycocyanin and improve its heat resistance.
We iGEMer are all biologic magicians and creat more possibilities.
[1]G. Martelli, C. Folli, L. Visai, M. Daglia, D. Ferrari Thermal stability improvement of blue colorant C-Phycocyanin from Spirulina platensis for food industry applications Process Biochemistry, 49 (1) (2014), pp. 154-159
[2]P. Pleonsil, S. Soogarun, Y. Suwanwong Anti-oxidant activity of holo- and apo-c-phycocyanin and their protective effects on human erythrocytes Int J Biol Macromol, 60 (September) (2013), pp. 393-398
[3]J. Zheng, T. Inoguchi, S. Sasaki, Y. Maeda, M.F. McCarty, M.Fujii, N. Ikeda, K. Kobayashi, N. Sonoda, R. Takayanagi Phycocyanin and phycocyanobilin from Spirulina platensisprotect against diabetic nephropathy by inhibiting oxidative stress Am J Physiol Regul Integr Comp Physiol, 304 (January (2))(2013), pp. R110-R120
[4]S.M. Shanab, S.S. Mostafa, E.A. Shalaby, G.I. Mahmoud Aqueous extracts of microalgae exhibit antioxidant and anticancer activities Asian Pac J Trop Biomed, 2 (August (8)) (2012), pp. 608-615
[5]S.R. Shih, K.N. Tsai, Y.S. Li, C.C. Chueh, E.C. Chan Inhibition of enterovirus 71-induced apoptosis by allophycocyanin isolated from a blue-green alga Spirulina platensis J Med Virol, 70 (May (1)) (2003), pp. 119-125
[6]N.T. Eriksen Production of Phycocyanin-a pigment with application in biology, biotechnology, foods and medicine Appl Microbiol Biotechnol, 80 (2008), pp. 1-14
[7]S.T. Silveira, J.F.M. Burkert, J.A.V. Costa, C.A.V. Burkert, S.J.Kalil Optimization of Phycocyanin extraction from Spirulina platensis using factorial design Bioresour Technol, 98 (2007), pp. 1629-1634
[8]I. Chentir, M. Hamdi, S. Li, A. Doumandji, G.Markou, M. Nasri Stability, bio-functionality and bio-activity of crude phycocyanin from a two-phase cultured Saharian Arthrospirasp. strain Algal Research, 35 (2018), pp. 395-406
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ID:IGEM_ECUST
ECUST_China
East China University of Science and Technology
Shanghai,China
