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Characterization of exopolysaccharides (EPS) extracted from marine microalgae species
(Nannochloropsis oceanica and Tetraselmis chuii) in Terengganu

1 Adila Soffia Mohamad Rejab , Mohd Effendy Abd Wahid, 1,2,4 Wan Nurul Nadiah Wan Rasdi,
* 1,2,3
1 Mohamad Khairi Mohd Zainol

1 Faculty of Fisheries and Food Science, Universiti Malaysia Terengganu, 21030 Kuala Terengganu,
Terengganu, Malaysia.
2 Institute of Tropical Aquaculture and Fisheries, Universiti Malaysia Terengganu, 21030 Kuala
Terengganu, Terengganu, Malaysia.
3 Institute of Marine Biotechnology, Universiti Malaysia Terengganu, 21030 Kuala Terengganu,
Terengganu, Malaysia.
4 Institute of Tropical Biodiversity and Sustainable Development, Universiti Malaysia Terengganu,
21030 Kuala Terengganu, Terengganu, Malaysia.

*Corresponding author: adilasoffia@gmail.com

Abstract:

Microalgae are gaining wide attention in recent years as potential natural resources in human life such
as medical and biotechnology aspects. The adaptation of microalgae to various environmental conditions
depends on the species. The growth and biochemical composition could vary based on their culture,
particularly the salinity level. Thus, finding suitable culture conditions for specific microalgae species
is important for optimal growth and biochemical composition. This study aimed to determine the growth
curve and characterize the exopolysaccharides (EPS) of two marine species (Nannochlopsis oceanica
and Tetraselmis chuii) of microalgae in different salinity (30 ppt, 40 ppt and 50 ppt). This study used
the centrifugation method to extract the EPS compound. Scanning Electron Micrograph (SEM) and
High-Performance Liquid Chromatography Refractive Index Detector (HPLC-RID) were used to
characterize the EPS. The various salinity level resulted in differences between tested microalgae species
in achieving the stationary phase. Besides, the amounts of sugar in the microalgae also vary. T. chuii
showed a shorter cultivation time which is less than 15 days to achieve the stationary phase for all
salinity levels and produced a high amount of sucrose which was 10.603 mg/mL at 30 ppt while N.
oceanica resulted in 10.578 mg/mL at 40 ppt. Sucrose, glucose and mannose were also found in T. chuii
when salinity was 40 ppt while in N. oceanica only sucrose and glucose existed. This can be concluded
that T. chuii was better than N. oceanica in EPS production. The finding of this study can be used to
improve the cultivation and extraction protocol of these species of marine microalgae to get the
compound for other specific purposes especially medical and aquaculture by manipulating the salinity
variation of the culture medium.

Keywords: characterization, exopolysaccharides, extraction, marine microalgae, Terengganu