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The Scientific World Journal
Volume 2014, Article ID 401265, 13 pages
http://dx.doi.org/10.1155/2014/401265
Research Article

Effect of Selenate on Viability and Selenomethionine Accumulation of Chlorella sorokiniana Grown in Batch Culture

1Algal Biotechnology Group, Department of Chemistry and Material Sciences, Faculty of Experimental Sciences, University of Huelva, Campus el Carmen, Avenida de las Fuerzas Armadas s/n, 21007 Huelva, Spain
2Department of Food Technology and Biotechnology, Faculty of Chemistry, Brno University of Technology, Purkyňova 118, 61200 Brno, Czech Republic
3Algal Biotechnology Group, International Centre for Environmental Research (CIECEM), Parque Dunar s/n, Matalascaňas, Almonte, 21760 Huelva, Spain
4Department of Environmental Biology and Public Health, University of Huelva, Campus el Carmen, 21007 Huelva, Spain
5Department of Chemistry and Material Sciences, University of Huelva, Campus el Carmen, 21007 Huelva, Spain
6University of Applied Science, Giessen, Wiesenstrasse 14, 35390 Giessen, Germany

Received 25 August 2013; Accepted 31 October 2013; Published 29 January 2014

Academic Editors: T. Betakova and D. Zhou

Copyright © 2014 Živan Gojkovic et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The aim of this work was to study the effect of Se(+VI) on viability, cell morphology, and selenomethionine accumulation of the green alga Chlorella sorokiniana grown in batch cultures. Culture exposed to sublethal Se concentrations of 40 mg·L−1 (212 μM) decreased growth rates for about 25% compared to control. A selenate EC50 value of 45 mg·L−1 (238.2 μM) was determined. Results showed that chlorophyll and carotenoids contents were not affected by Se exposure, while oxygen evolution decreased by half. Ultrastructural studies revealed granular stroma, fingerprint-like appearance of thylakoids which did not compromise cell activity. Unlike control cultures, SDS PAGE electrophoresis of crude extracts from selenate-exposed cell cultures revealed appearance of a protein band identified as 53 kDa Rubisco large subunit of Chlorella sorokiniana, suggesting that selenate affects expression of the corresponding chloroplast gene as this subunit is encoded in the chloroplast DNA. Results revealed that the microalga was able to accumulate up to 140 mg·kg−1 of SeMet in 120 h of cultivation. This paper shows that Chlorella sorokiniana biomass can be enriched in the high value aminoacid SeMet in batch cultures, while keeping photochemical viability and carbon dioxide fixation activity intact, if exposed to suitable sublethal concentrations of Se.