Thraustochytrid as a potential source of carotenoids

Abstract

Thraustochytrids, marine protists whose dominant genera are Thraustochytrium and Schizochytrium, belong to the kingdom Chromista and are known as an industrial source of DHA. We describe here that thraustochytrid strain KH105, isolated as a DHA producer, also accumulates significant levels of β-carotene and xanthophylls including canthaxanthin and astaxanthin. A 4-d cultivation using a medium composed of 10% glucose and less than 0.3% of nitrogen sources in a half-concentration of seawater gave an astaxanthin production up to 6.1 mg/L, and canthaxanthin content reached more than 10 mg/L under conditions where a higher concentration of nitrogen sources (6%) was employed. It might be advantageous in mass production systems for these carotenoids to be extracted readily by simply suspending the cells with organic solvents such as acetone and chloroform. Analyses on the morphological and life history features of the KH105 strain revealed that it belongs to the genus Schizochytrium. This particular species of thraustochytrids is thus considered to be a promising source of xanthophylls as well as DHA for use in the food industry.Paper no. J10395 in JAOCS 80, 789-794 (August 2003).

Carotenoid analysis of locally isolated Thraustochytrids and their potential as an alternative fish feed for Oreochromis niloticus (Nile tilapia)

“…Thraustochytrids have been reported as producers of carotenoids by Aki et al(2003). This was the first report on the carotenoid production in Schizochytrium sp.…”

“…Their pigments were extracted using chloroform or acetone resolved on a thin-layer silicaplate. According to their report, this organism produces carotenoid-like pigments due to its fatty acid profile and molecular phylogenetics Aki et al (2003) pointed out that carotenoids in microorganisms were used to scavenge oxygen radicals generated, at least partly, byphotochemical reactions. Carotenoids, being secondarymetabolites, are not essential for the growth of the organism; however, environmental factors may or may not lead to the production of these carotenoids.…”

“…The presence of carotenoids in our thraustochytrid isolates makes these organisms economically important. According to some investigators, β-carotene and lutein have several health benefits (Carmona et al 2003, Aki et al 2003, Ganuza et al 2008). β-carotene has long been known to have antioxidant activity while lutein is being extensively studied in relation to eye health for the prevention of cataracts and age-related macular degeneration.Other carotenoids like canthaxanthin display similar or slightly reduced levels of antioxidant effect compared to astaxanthin.…”

“…Aki et al (2003) added that on lowof β-carotene to astaxanthin occurs via ketocarotenoids like cantaxathin and echinenone. However, the effect of variation in a number of parameters such as the physicalfactors (pH and temperature) and nutritional factors (carbon and nitrogen sources) duringthe culture can alter the relative quantities ofthe carotenoid produced.…”

Glass Bead-based Genetic Transformation:An Efficient Method for Transformation of Thraustochytrid Microorganisms

“…Thraustochytrids are marine eukaryotic microorganisms that have attracted great attention owing to their capacity for accumulation of polyunsaturated fatty acids PUFAs , such as docosahexaenoic acid DHA , in large amounts 1 and their ability to biosynthesize useful substances, such as squalene 2 and astaxanthin 3 . Genetic manipulation techniques, such as introduction and destruction of genes, are necessary for elucidation of biosynthetic pathways and molecular breeding for fermentative production of useful substances.…”