Raw Glycerol and Parboiled Rice Effluent for Carotenoid Production: Effect of the Composition of Culture Medium and Initial pH


Carolina Moroni Silva, Thais de Matos de Borba, Susana Juliano Kalil and Janaína Fernandes de Medeiros Burkert*

Federal University of Rio Grande (FURG), Chemistry and Food School (EQA), PO Box 474, BR-96203-900 Rio Grande, RS, Brazil

Article history:
Received    August 27, 2015
Accepted   June 29, 2016

Key words:
natural pigments, by-products, Plackett-Burman design, Xanthophyllomonas dendrorhous

Search for naturally grown food has stimulated the biotechnological production of carotenoids. Therefore, the use of the yeast Xanthophyllomonas dendrorhous has been researched due to its abilities to assimilate different sources as substrates and to produce high amounts of carotenoids. Furthermore, alternative sources have been used as the culture medium to reduce costs and environmental impact. A potent carotenoid is astaxanthin in view of its health-promoting and antioxidative properties. It consists of different geometrical isomers with trans and cis configuration. In X. dendrorhous this carotenoid is mostly found in the trans form, but cis isomers can also be found. Carotenoid production was investigated in culture medium containing by-products such as raw glycerol (from biodiesel) and parboiled rice effluent. The effects of the culture medium components on biomass concentration and specific and volumetric productions of carotenoids were verified by the Plackett-Burman design. Cultivations were carried out with yeast Xanthophyllomonas dendrorhous NRRL Y-17268 at 25 °C and 150 rpm for 168 h. In this study, maximum production of carotenoids was obtained under the following conditions (in g/L): raw glycerol 10, glucose 10, yeast extract 10, malt extract 10 and peptone 1 at pH=6. Resulting specific and volumetric productions of carotenoids were 326.8 and 4.1 μg/g, respectively.


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