Biogenic calcite particles from microalgae—Coccoliths as a potential raw material

Abstract

Synthetic calcite (CaCO3) particles are found in a broad range of applications. The geometry of particles produced from limestone or precipitation are versatile but limited to basic shapes. The microalga Emiliania huxleyi produces micro‐structured calcite platelets, called coccoliths. This article presents the results of an application‐orientated study, which includes characteristic values also used in the calcite industry for particle evaluation. It is demonstrated that coccoliths are significantly different from all industrial particles produced so far. Coccoliths are porous particles, mainly consisted of calcium carbonate, with further elements such as Mg, Si, Sr, and Fe often embedded in their structure. Their structure is extremely sophisticated, while the overall particle morphology and particle size distribution are homogeneous. This study gives a first inside into the potential of these exceptional objects and may set further impulses for their utilization in specific calcite particle applications.

In Vivo Shaping of Inorganic Functional Devices using Microalgae

“…This leads to an expansion of the spectrum of structures and multifunctional materials are created. In this regard, especially the shells of microalgae, like the frustules of diatoms or the coccoliths of coccolithophores are of great interest 1–3…”

“…Coccolithophores like Emiliania huxleyi are unicellular marine microalgae, which cover themselves with elaborated finely‐patterned calcite (CaCO 3 ) disks, called coccoliths ( Figure 1 ). Coccoliths are mesoporous, 3D sieve‐like structures of about 3 µm in diameter with pore diameters ranging from micrometer to nanometer scale and possess a total pore volume of 0.05 cm 3 g −1 2,4. The overall geometry has a specific surface area of 19 m 2 g −1 2.…”

“…Coccoliths are mesoporous, 3D sieve‐like structures of about 3 µm in diameter with pore diameters ranging from micrometer to nanometer scale and possess a total pore volume of 0.05 cm 3 g −1 2,4. The overall geometry has a specific surface area of 19 m 2 g −1 2. Coccoliths are produced inside the cell under genetic control in special organelles, the coccolith vesicles (cv) 5,6.…”

“…Each E. huxleyi cell is surrounded by 10–15 coccoliths, but the coccoliths are easily detached and new coccoliths are constantly built. The coccoliths can be obtained in high yields of around 5 g L −1 d −1 2…”

New Possibilities to Design Biogenic Calcite Particles. Influence of Cultivation Parameters and Purification on Coccolith Properties

“…Die siebähnlich geformten Partikeln weisen interessante chemische, physikalische und partikeltechnische Eigenschaften auf, sind biokompatibel und wurden deshalb bereits für den Einsatz in verschiedensten Applikationen vorgeschlagen [16 -18]. Sie sind dadurch nicht reinweiß, sondern besitzen eine leichte Gelbfärbung [17]. B. bereits gezeigt, dass es möglich ist, Enzyme auf der Coccolithenoberfläche zu immobilisieren [19].…”