Morphology, nutritional composition and accumulation of astaxanthin in Oedocladium cirratum

PITTA-ALVAREZ S.; MARSILI S.; CERÓN-GARCÍA M.C.; REARTE T.A.; VELEZ C.G.

Paraná

Congreso; Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2018

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

The objective of the present work is to evaluate the morphological characteristics, nutritional composition and accumulation of carotenoids with special emphasis on astaxanthin, product of great commercial interest, due to the effect of nitrogen limitation on the algae O. cirratum (UTEX LB 1532) of habit terrestrial (humid soils). As an adaptation to face conditions of rapid desiccation of soils and high intensities of sunlight, the vegetative cells can develop thick cell walls and accumulate a high amount of carotenoids, differentiating into acinetas. Cultures for vegetative growth were performed in 1-liter bioreactors of standard mineralized medium, with aeration and continuous light at 23 ±1 °C and then this culture was subjected to nutritional stress conditions in standard mineralized medium without N source for production of akynetes rich in astaxanthin. The morphological and nutritional characteristics of the vegetative cells and the acinetas were evaluated. Lipids (Bligh and Dyer, 1959), pigments (Wellbrum, 1994), carbohydrates (Dubois, 1956), proteins (Lowry, 1951) and Astaxanthin (HPLC, column Lichrospher 100, RP-18) were determined. Cultures for vegetative growth were performed in 1-liter bioreactors of standard mineralized medium, with aeration and continuous light at 23 ±1 °C and then this culture was subjected to nutritional stress conditions in standard mineralized medium without N source for production of akynetes rich in astaxanthin. This work presents the observations under growing and stress conditions and the nutritional composition of vegetative cells: total lipids. (5.27 ± 0.77%); protein (13,7 ± 1,5%); carbohydrates (45.7 ± 4.2%); chlorophyll a and b (2.42 ±0.66 and 4.49 ± 0.39 mg / g) and akynetes: total lipids (23.7 ± 3.16%); proteins (5,4 ± 2,86%); carbohydrates (13,7±3,4%); chlorophyll a and b (0,99 ±0.28 and 1,15 ± 0.11 mg / g); total carotenoids (17,13 ± 1,43 mg / g). O. cirratum has a high potential for the production of astaxanthin since it is possible to induce the accumulation by modifying the culture conditions obtaining high levels compared, mainly, with H. pluvialis. It is believed that by optimizing the vegetative growth culture medium and stress conditions, better results can be obtained.