Growth and B-Phycoerythrin Production of Red Microalga Porphyridium purpureum (Porphyridiales, Rhodophyta) under Different Carbon Supply

Abstract

Red microalga Porphyridium purpureum (Bory) Drew is a well-known object of biotechnology due to its unique ability to synthesize a wide range of biologically active compounds. Enough minerals in an accessible form in a medium are a prerequisite for maintaining a high growth rate of P. purpureum. Carbon is the main element of microalgal biomass and is a component of all organic compounds. The work aimed to study the morphological features of cells and the accumulation and production of B-phycoerythrin and total protein in P. purpureum biomass in different ways of supplying CO2 into the culture. In Variant 1, CO2 was directly injected into a gas–air mixture (2–3 percent v/v) used for culture bubbling via capillary. In Variant 2, the air was supplied to the culture through the aquarium sparger. Variant 3 was like the first one but without the additional introduction of carbon dioxide. The application of the method for sparging atmospheric air led to a significant increase in both the productivity of the P. purpureum and the rate of protein and B-phycoerythrin synthesis in comparison with growing it using the air without spraying (two-and-a-half times, five times, and more than eight times, respectively). Moreover, there were significant changes in the morphological structure of P. purpureum cells, which were visualized both by microscopy and by changes in the color of the culture. Based on the experimental data obtained, the variants for the carbon supply experiment were ranked as follows: Variant 1 is better than Variant 2 and Variant 3. The use of atomization as a technological method made it possible to speed up the transfer of carbon dioxide from the air to the medium, which helped to keep the growth rate of P. purpureum biomass and B-phycoerythrin accumulation high.

Recent advances and fundamentals of microalgae cultivation technology

“…This is consistent with several publications, in which CO 2 supplementation was directly compared to other approaches. [13,15,74] Moreover, strain selection and genetic engineering to increase pigment and food component production proved more effective than increasing microalgae productivity through increased CO 2 fixation or bacterial interactions.…”

“…[13,74,104] These approaches fall into the category of bioreactor design, whereas in other cases a single parameter was analyzed. The management of pH levels between 7 and 8 for microalgae growing at high ammonia concentrations, [89] the application of light-shielding hydrogel for nitrogen removal by the microalgae-bacteria cocultures; [103] air spraying in combination with CO 2 supplementation; [13] the decrease of the light pass in combination with increased aeration and bacterial nitrification rates; [52,75] and the optimization of the phosphorus and nitrogen content of the media for lipid production, [104] produced the most significant effects on microalgae productivity. [89] Notably, the majority of the analyzed publications (44 of 47 studies containing strain productivity information) represent photoautotrophic or mixotrophic cultivation of microalgae in photobioreactors.…”

“…Another interesting investigation has revealed that air spraying boosts protein synthesis five times and B‐phycoerythrin synthesis eight times, with an additional 20% rise observed with extra CO 2 supplementation. [ 13 ]…”

“…Microalgae are a group of photosynthetic organisms that are found in different habitats all over the world. [1,2] Nowadays microalgae are increasingly used in industry as a feed for farmed fish or livestock, [3][4][5] as well as the production of food, drugs or drug components such as 𝛽-carotene for humans, [6,7] omega-3 polyunsaturated fatty acid, [8][9][10][11] food colorings including astaxanthin, [7,12] and phycoerythrin, [13][14][15] and many other carotenoid antioxidants with anticancer and anti-inflammatory activities. [16][17][18][19][20] Gene engineered microalgae have been tested in protein drug development [21] and edible vaccine production.…”

Impact of Biomass Drying Process on the Extraction Efficiency of C-Phycoerythrin

“…The primary source of industrial-grade PE are strains from the red algae Porphyridium sp., especially P. cruentum [ 18 , 28 , 29 , 30 , 31 , 32 ] and P. purpureum [ 17 , 18 , 19 , 33 , 34 ]. However, this genus is also known as a primary source of sulfated EPS; therefore, the available protocols for extracting PE are adapted to the unique requirements of these unicellular red algae, which makes the extraction and recovery process tedious and time-consuming [ 35 ].…”