Isochrysis sp.

• Isochrysis is a genus of haptophytes and known as brown-golden marine microalgae (Heimann & Huerlimann, 2015).
• They are famous because they can produce Docosahexaenoic (DHA), a very long chain polyunsaturated fatty acid (PUFA) of significant health and nutritional value. (López et. al., 1992).
• Currently, SBC’s microalgae library has a total of 31 locally isolated Isochrysis sp.

Natural Habitat

• Isochrysis sp. can be found in marine environment (Tomas, 1997).
• SBC’s strains were isolated from marine environment.
• Number of strains isolated in Sarawak::

Characteristics

• Size (nm)
  • Ranged from 4 to 6 µm (Thu et al., 2015).
  • The Isochrysis strains in the SBC's microalgae library ranged from 5 to10 µm in diameter.
• Flagella
  • Two flagellates (https://www.algaebarn.com/blog/phytoplankton/isochrysis-the-microalgal-reef-aquarium-superfood/)
• Motile
  • Move in helical movement (https://www.algaebarn.com/blog/phytoplankton/isochrysis-the-microalgal-reef-aquarium-superfood/)
• Shape
  • Oval
• Any other published scientific info
  • Contain one or two chloroplasts and at least one species is covered with up to four layers of organic scales (Liu et al. 2008).

Algae Bioeconomy/Industry

• Aquafeed
  • Direct or indirect feed sources in hatchery as nutritional diet for early juveniles of farmed fish, shellfish, and shrimp (Marchetti et al., 2012).
  • Suitable for aquaculture due to their small size ranged from 4–6 μm which ease the digestibility (Thu et al., 2015) and high nutritional value and high polyunsaturated fatty acids (PUFAs) contents, such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA).
  • Isochyrisis sp. is made into paste or living culture product. For example, freeze dried Isochyrisis “Tahitianstrain” T-ISO (https://algae.proviron.com/our-prime-microalgae/isoprime/) is used to feed on rotifer and copepod.
• Bioremediation
  • Isochrysis zhanjiangensis was cultivated in wastewater and found out that a total of 78% active phosphorus, 100% ammonia nitrogen, 62.3% nitrite nitrogen and 84.7% nitrate nitrogen were eliminated (Zheng et.al., 2011) The microalgae not only act as bioremediation but also to produce biomass material at the same time.
• Therapeutics and pharmaceuticals industry
  • Isolated polysaccharides from Isochrysis galbana (IPSI-A, IPSI-B and IPSII) demonstrated antioxidant activity and free radical scavenging activity (Sun et al., 2014) which may reduce the risk of arthritis, cancer and neurodegenerative diseases (Lee et al., 2010).
  • Fucoxanthin found in Isochrysis galbana exhibits antioxidant activities (Goss and Jakob, 2010) which comparable to other carotenoid such as zeaxanthin, β-carotene and lutein (Nomura et al., 1997).

References

Goss, R. & Jakob, T. (2010). Regulation and function of xanthophyll cycle-dependent photoprotection in algae. Photosynthesis research, 106(1-2), 103-122.

Heimann, K. & Huerlimann, R. (2015). Chapter 3 – Microalgal classification: Major classes and genera of commercial microalgal species. Handbook of Marine Microalgae. Biotechnology Advances, 25 – 41.

Lee, S. H., Lee, J. B., Lee, K. W. & Jeon, Y. J. (2010). Antioxidant properties of tidal pool microalgae, Halochlorococcum porphyrae and Oltamannsiellopsis unicellularis from Jeju Island, Korea. Algae, 25(1), 45-56.

Liu, C. F., Wu, X., & Gao, Y. M. (2008). The morphological observation and comparison of ultrastructure in two alga species Isochrysis zhanjiangensis sp. nov and Isochrysis galban Parke [J]. Journal of Dalian Fisheries University, 4.

López, D., Molina, E., Srinchez, J.A., Garcia, J.L. & Garcia, F. (1992). Isolation of clones of Isochrysis galbana rich in eicosapentaenoic acid. Aquaculture, 102(4), 363 – 371.

Marchetti, J., Bougaran, G., Le Dean, L., Mégrier, C., Lukomska, E., Kaas, R. & Cadoret, J. P. (2012). Optimizing conditions for the continuous culture of Isochrysis affinis galbana relevant to commercial hatcheries. Aquaculture, 326, 106-115.

Nomura, T., Kikuchi, M., Kubodera, A. & Kawakami, Y. (1997). Proton‐donative antioxidant activity of fucoxanthin with 1, 1‐diphenyl‐2‐picrylhydrazyl (DPPH). IUBMB Life. 42(2), 361-370.

Sun, Y., Wang, H., Guo, G., Pu, Y. & Yan, B. (2014). The isolation and antioxidant activity of polysaccharides from the marine microalgae Isochrysis galbana. Carbohydrate polymers, 113, 22-31.

Thu, N. T. H., Anh, H. T. L., Hoang, M. H., Kim, D. D. & Hong, D. D. (2015). Study on biological characteristics of a newly isolated Vietnamese strain of microalga Isochrysis galbana Parke for utilizing as live aquaculture feed. Russian Journal of Marine Biology, 41(3), 203-211.

Tomas, C. R. (1997). Identifying marine phytoplankton. Chapter 5: The planktonic marine flagelattes. By Academic Press, Inc.

Zheng, J., Hao, J.M., Wang, B. & Shui, C. (2011). Bioremediation of Aquiculture Wastewater by Microalgae Isochrysis zhanjiangensis and Production of the Biomass Material. Key Engineering Materials. Vols. 460-461, 491-495.

López, D., Molina, E., Srinchez, J.A., Garcia, J.L. & Garcia, F., Isolation of clones of Isochrysis galbana rich in eicosapentaenoic acid. Aquaculture (in press).