Recebido em 5/9/08; aceito em 29/4/09; publicado na web em 28/10/09 CAROTENOIDS PRODUCTION: MICROORGANISMS AS SOURCE OF NATURAL DYES. Carotenoids are natural dyes synthesized by plants, algae and microorganisms. Application in many sectors can be found, as food dyeing and supplementation, pharmaceuticals, cosmetics and animal feed. Recent investigations have shown their ability to reduce the risks for many degenerative diseases like cancer, heart diseases, cataract and macular degeneration. An advantage of microbial carotenoids is the fact that the cultivation in controlled conditions is not dependent of climate, season or soil composition. In this review the advances in bio-production of carotenoids are presented, discussing the main factors that influence the microbial production of these dyes in different systems.

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The increasing demand for carotenoids by industries has drawn attention to their bio-production. Since pigments are intracellular, extraction steps are then needed after cell cultivation. In this work, different strategies for extraction of carotenoid pigments from Sporidiobolus salmonicolor (CBS 2636) were studied. Different solvents (dimethyl sulfoxide, petroleum ether, hexane, ethyl acetate, chloroform, and acetone), liquid N 2 , and diatomaceous earth were used to disrupt the cell and thus release the intracellular carotenoids. The results of this study showed that when multiple solvents were used, a synergistic effect on the extent of carotenoids recovery was obtained. Maximum concentration of total carotenoids (913 μg/L) was obtained in the treatment using liquid N 2 and dimethyl sulfoxide to disrupt the cell, followed by the extraction with a solution of acetone/methanol (7:3, v/v).

This work studied the cultivation conditions for the production of carotenoids by Sporidiobolus salmonicolor (CBS 2636) in a bioreactor. A Plackett-Burman design was used for the screening of the most important factors, followed by a complete second order design, to maximise the concentration of total carotenoids. The maximum concentration of 3425.9 lg L )1 of total carotenoids was obtained in a medium containing 80 g L )1 glucose, 15 g L )1 peptone and 5 g L )1 malt extract, with an aeration rate 1.5 vvm, 180 r.p.m., 25°C and an initial pH of 4.0. Fermentation kinetics showed that the maximum concentration of total carotenoids was reached after 90 h of fermentation. Carotenoid bio-production was partially associated with cell growth. The specific carotenoid production (Y P ⁄ X ) was 238 lg carotenoids ⁄ g cells, whereas Y P ⁄ S (substrate to product yield) was 41.3 lg g )1 . The specific growth rate (l x ) was 0.045 h )1 . The highest cell and total carotenoid productivity were 0.19 g L )1 h )1 and 56.9 lg L )1 h )1 , respectively.

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