Abstract
Purpose: :
Lipophilic nutritional factors such as omega-3 fatty acids and carotenoids exert several important biological effects that may protect against retinal degenerative diseases such as age-related macular degeneration (AMD). The upcoming Age-Related Eye Disease Study II (AREDS II) is specifically focusing on the potential protective roles of the macular carotenoids (lutein and zeaxanthin) and omega-3 fatty acids (EPA and DHA); however, there are no reports of a single natural source that supplies both carotenoids and omega-3 fatty acids in appreciable quantities. In this work we have explored the potential of Chlorella protothecoides, a food grade algae, as a sole source of lutein, DHA, and other fatty acids.
Methods: :
Freshwater algae Chlorella protothecoides CS 41 was cultivated in Woods Hole MBL medium in 250 ml Erlenmeyer flasks and incubated at 20 °C under continuous shaking (180 rpm) in dark/light alternating cycles on a rotary shaker at 180 rpm for 240 h. The cell mass was harvested and analyzed for carotenoids and fatty acids by HPLC and GC coupled with in-line single quadrupole mass spectrometers (MS), respectively.
Results: :
Chlorella protothecoides displayed specific growth rate (µ max) and maximum biomass of 0.25 h-1 and 10.68 g/l in 240 h. The production profile indicated that lutein was the major carotenoid (95% w/w) produced throughout fermentation. At the end of the fermentation run (240 h), the total lutein content was observed to be 8.14±0.6 mg/l. Lipid analysis revealed that Chlorella protothecoides accumulates fatty acids such as palmitic (C16), stearic (C18), oleic (C18:1 (n-6)) and arachidonic (C20:4 (n-6)) Most importantly, it displayed a considerable amount of DHA (C 22:6) accumulation (15 -23 % w/w of total lipid).
Conclusions: :
Production of lipids and carotenoids by Chlorella protothecoides suggests that it could act as a new generation, single source, nutritionally beneficial, dietary source of lutein and DHA for human ocular health that would be especially appealing to vegetarians and those interested "all natural" nutrients.
Keywords: carotenoids/carotenoid binding proteins • nutritional factors • age-related macular degeneration