Thailand Institute of Scientific and Technological Research
Title: Effects of temperature on the elemental and biochemical composition of a marine microalga
Biography: Narin Chansawang
A change in environmental conditions often leads to changes of physiology and biochemical composition of microalgae. Temperature is an important environmental factor regulating the growth of microalgae. In this study, the elemental and biochemical composition were measured in the marine haptophyte Emiliania huxleyi (clone CCMP 1516) in nutrient replete conditions. Triplicate cultures were incubated from 14oC to 22oC. Culture were illuminated under photon flux densities (PFD) 600 μmol photon m−2 s−1 on a 14L:10D cycle. The growth rate (GR) of E. huxleyi increased with temperature from 0.41 d-1 at 14oC to 1.12 d-1 at 22oC. Cell volume also varied with temperature. Cellular chlorophyll a, nitrogen, phosphorus, carbon and contents were also lower at 22oC than other temperatures. Protein, total amino acids from free and combined amino acid, and total pigments [mol accessory pigment (mol chl a)-1] were decreased with increasing temperature; however, the opposite response was observed in fatty acids. Myristic (C14:0) and oleic (C18:1) acid were predominant fatty acid approximately 18.1-22.9% total fatty acid. Eicosapentanoic acid (EPA, C20:5n3) and docosahexaenoic acid (DHA, C22:6n3) as polyunsaturated fatty acids (PUFAs) were found in E. huxleyi. The content of the highest DHA was 8.2 % total fatty acid at the low temperature while EPA content did not change (3-4 % total fatty acid) with temperature. The highest level of n-3 to n-6 ratio of the remaining fatty acids (~ 2) was achieved at 14oC of E. huxleyi which would make E. huxleyi suitable as a feed stock for aquaculture.