Abstract

Aims To evaluate an aqueous extract of Macrocystis pyrifera as a nutrient source for the production of carotenoids by a marine Rhodotorula mucilaginosa isolated from seaweed samples. Materials and Results The effect of different culture conditions on the concentration of biomass and total pigments was evaluated using a Box-Behnken experimental design. The seaweed extract contained 15% w w(-1) of protein and 20% w w(-1) of carbohydrate; the main sugar in this fraction was trehalose (78%). The culture conditions that maximize the total pigment concentration (1 center dot 84 +/- 0 center dot 03 mg l(-1)) were initial pH equal to 7, yeast extract as nitrogen source at a concentration of 4 g l(-1), seaweed extract concentration at 25% v v(-1), incubation performed at 25 degrees C and 150 rev min(-1) during 6 days. Under optimal growth conditions, three carotenoids were identified among the pigments produced by R. mucilaginosa, lycopene (38 center dot 4 +/- 9 center dot 4%), beta-carotene (21 center dot 8 +/- 1 center dot 5%) and astaxanthin (1 center dot 8 +/- 0 center dot 3%). Conclusions Carotenoids of commercial interest (lycopene, beta-carotene and astaxanthin) can be produced using a marine R. mucilaginosa cultivated with an aqueous extract of M. pyrifera as nutrient source. The total pigment concentration in the culture ranged between 0 center dot 82 and 1 center dot 84 mg l(-1), and was significantly affected by the concentration of the seaweed extract, and yeast extract. Significance and Impact of the Study This work demonstrates that M. pyrifera can be used as a nutrient source for the production of carotenoids by the marine yeast.