Authors: Kim J M Mulders Packo P Lamers René H Wijffels Dirk E Martens
Publish Date: 2014/11/05
Volume: 99, Issue: 4, Pages: 1873-1884
Abstract
The effect of nitrogen replenishment on the kinetics of secondary carotenoids triacylglycerol TAG and primary cell components was studied in nitrogenstarved Chromochloris zofingiensis Chlorophyta an oleaginous and carotenogenic microalga Nitrogen resupplied after a period of starvation was initially consumed at a more than four times higher rate than in an equivalent nitrogenreplete culture Simultaneously chlorophylls primary carotenoids polar membrane lipids and proteins were rapidly produced After 2 days the contents of these primary metabolites as well as the nitrogen consumption rate and the overall biomass production rate had returned to values equivalent to those of cells grown under nitrogenreplete conditions indicating that culture recovery required 2 days Nitrogen resupply was immediately followed by rapid degradation of TAG and starch suggesting that these metabolites served as carbon and energy source for the recovery process Also the secondary carotenoids canthaxanthin and ketolutein were rapidly degraded upon nitrogen resupply whereas degradation of astaxanthin the main secondary carotenoid started only when the cells were fully recovered 2 days after nitrogen resupply This is the first time that such culture recovery has been described in detail and moreover that astaxanthin was found to be not immediately degraded after nitrogen resupply The observed rapid recovery of C zofingiensis and the delay in astaxanthin degradation suggest that a repeated batch cultivation may result in a higher secondary carotenoid productivity than a series of classical single batch cultivationsWe gratefully thank Yannick Weesepoel of Wageningen University Laboratory of Food Chemistry for performing the pigment identification and quantification and helping with the Dumas analyses This work was supported by FeyeCon DI and by grants from Rijksdienst voor Ondernemend Nederland Project no FND09014
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