Profile of fatty acids in freshwater microalgae species, family Selenastraceae, Chlorophyta, as chemotaxonomic characteristic and prospecting applicability

Abstract

The paper proposes lifting the profile of the fatty acid composition of species of freshwater microalgae, green family Selenastraceae (Chlorophyta). The fatty acid profile is considered as chemotaxonomic characteristic in a polyphasic taxonomic approach, the data obtained by traditional taxonomy based on morphological characters and the data obtained by analysis of 18S rRNA, another work in parallel. Polyphase approaches are also employed for digital image analysis of cells, and by analysis of the monomer composition of extracellular polysaccharides as well as chemotaxonomic characteristics. These other approaches are being conducted in parallel jobs related to the project theme. One goal of these approaches is to provide subsidies for the use of DNA barcode technique that can solve problems of polymorphism and cryptic species in this microalgae group. The profiles obtained will be part of a database species-associated that are taxonomically resolved and cryopreserved in a genebank. The work also aims at prospecting (which will be extended to other groups of microalgae) of the composition of fatty acids that can potentially be used in the nutrition of animals with economic interest, and in human nutrition, such as poly-fatty acid unsaturated, or in other applications such as fuels, for example. The choice of species will give priority to those that are the object of obtaining the DNA barcode and obtaining cryopreservation protocols, such as species of the family concerned with problems recognized taxonomic. These species are being collected and isolated in axenic cultures, from 22 UGRH Units (Water Resources Management) of the State of São Paulo (FAPESP Thematic Project 2011/50054-4). The survey will be done in three different ages of growth: lag, exponential and stationary growth in cultures considered "normal", ie, without the use of stress factors. These factors will only be used if the profile shows a fatty acid that can be considered of "high interest" to investigate whether such economic factors will increase their production. (AU)