TITLE:
Characterization of the Lipid Components in Desmodesmus and Scenedesmus Strains: Lipid Content, Lipid Classes and Fatty Acid Profile
AUTHORS:
Carolina Vieira Viegas, Gisel Chenard Díaz, Yordanka Reyes Cruz, Leonardo Brantes Bacellar Mendes
KEYWORDS:
Microalgae, Desmodesmus sp., Scenedesmus sp.
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.11 No.12,
December
24,
2020
ABSTRACT: The lipid composition in terms of the amount of
neutral lipids, free fatty acids and polar lipid content is of great importance
to make full use possible of this fraction and to define the suitability of its
application, either as a raw material for fuel production, nutraceutical
purposes or feed. In addition to the fatty components present in the lipid
extract, other components may be included, such as: carotenoids, pigments and
sterols. The microalgae studied in this work, Scenedesmus sp. and Desmodesmus sp., were subjected to the same growth conditions and evaluated for lipid
content, quantification and diversity of lipid components as well as its fatty
acid profile. For lipid determination two extraction methods were compared: the J: Schmid-Bondzynski-Ratzlaff and Bligh & Dyer method. For Desmodesmus sp. 5.43% ± 0.41% and 9.18% ± 0.33% of lipids were
obtained on an ash-free dry weight basis and for Scenedesmus sp. 12.46% ± 0.38% and 8.16% ± 0.42% of lipids were
obtained on anash-free dry weight basis using for both methods J: Schmid-Bondzynski-Ratzlaff and Bligh & Dyer, respectively. For the
identification of the main lipid components present in the extracts, the Thin
layer chromatography (TLC) technique was used. This made it possible, using a
simple and inexpensive method, to identify the compounds extracted by different
extraction methods, that is, it was possible to verify the selectivity of the
different extraction methods. In addition, it has been shown that using these
methods, widely described in the literature as methods of extracting lipids in
practice, extracts a wide
diversity of compounds. The major lipid class for both microalgae was fatty acids with amounts
between 23.62% - 38.02%. The triglycerides percentage in biomasses without
chemical treatment did not exceed 18.26%. In the lipid extract obtained with Bligh & Dyer, the microalgae Desmodesmus sp. presented 55.26% of unsaponifiable material, higher than the amount present
using the same extraction method for Scenedesmus sp. 49.06%. Among the main unsaponifiables identified are hydrocarbons
(carotenes) and sterols esters. The acid treatment of biomass, method J: Schmid-Bondzynski-Ratzlaff, showed selectivity of 72.84% and 76.66% for obtaining fatty material
from the microalgae Desmodesmus sp.
and Scenedesmus sp., respectively.
The results showed that depending on the method used for extraction, the lipid
fraction will be different in relation to the percentage of fatty components.