The freshwater alga Chroothece richteriana (Rhodophyta) as a potential source of lipids

During an ecological study of Chroothece (Rhodophyta) in a small river in a semi-arid region of south-east Spain it became clear that most of these cells had a high lipid content. This suggested potential uses in biotechnology, which has been investigated further. The colonies, which occur in full sunlight, are typically orange-brown. Most, perhaps all, the yellow-orange colour is associated with their high carotenoid content, with the carotenoid to chlorophyll ratio up to 2.7. The polyunsaturated fatty acyl composition of the glycerides was 35.3% of the dry weight. This consisted mainly of omega-3 (5.9%) and omega-6 (29.4%) fats. The relatively high proportion of docosahexaenoyl (1.78%), eicosapentaenoyl (14.15%), arachidonoyl (0.92%) and γ-linolenoyl (0.78%) suggests use for medical and dietary purposes. All cells have a high phycocyanin content whilst phycoerythrin is absent. The alga has a wide distribution globally and hence provides scope for selecting strains with optimum properties.