Cell Wall Composition and Compound Distribution

In addition to the taxonomic approach, investigating the distribution of bioactive macromolecules within the organism as well as construction and changes of algal cell wall is essential for a better understanding of environmental adaption and species-specific responses to nutritional conditions. 

With introduction of FPA detection, the technical device for a fast and simultaneous recording of IR spectra over a defined sample area and a better detection limit was given. In addition, the development of Raman methods such as CARS, SERS, and SRS could overcome basic problems such as low Raman scattering of cross sections and high sample fluorescence and, hence, opened it for the application in algae analysis. 

Although cell wall compounds of algae and their chemical structures are mostly known to date, their interaction and spatial arrangement inside the cell wall architecture still remains challenging. 

Investigating the cell wall polymer structure and arrangement in green seaweed Codium fragile by synchrotron FT-IR, Estevez and coworkers found a gradient of (l-4)- -D-mannan from the boundaries toward the center of mucron cell walls by increasing carbohydrate band intensities at 1151, 1092, 1061, and 1032 cm , respectively [150]. 

Another Raman study visualized the gradient of carotenoids in the diffusion boundary layer around the cells of the brown alga Fucus vesiculosus and green alga Ulva sp. [153]. 

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