AN ISOLATED PICOCHLORUM SP. FOR AQUACULTURE, FOOD AND BIOFUEL

More than 500 marine algal strains in Vietnam were screened for their ability to produce high lipids as one of the key criteria in this search. Among these, a Picochlorum sp. of Trebuxiophycean emerged as the species with the highest total lipid of 48.6% of its dry weight (DW), including 27.84% of docosahexaenoic acid (DHA). The remaining was mostly fatty acids with C16 and C18, which is appropriate for biofuels production. In addition, 20 different amino acids were identified with high ratio of essential amino acids. Subsequently, the impact of growth conditions, such as salinity, temperature and media, on the oleogenic potential of this species was investigated. The alga grew better (μ = 0.25 divisions per day) at a salinity of 0.5 M NaCl in enriched seawater medium (MD1) and at high temperature, but the lipid production was higher at 2 M NaCl in artificial medium (MD2) and at low temperature. Consequently, a two phase culture system should be recommended for obtaining high nutritional lipids and essential amino acids: MD1 can be used for biomass maximization at high temperature (25°C), cells can then be transferred into MD2, at lower temperature (15°C) for oleogenesis.