Effect of cooling in the night on the productivity and biochemical composition of Tetraselmis suecica

The effect of cooling at night on the 24 hour productivity and biochemical composition of Tetraselmis suecica cultivated in a tubular photobioreactor was determined. The hypothesis that cooling at night would decrease the night respiration rate and therefore enhance the net productivity was rejected. The productivity over a 24 hour period and biochemical composition were only influenced by the daily light input. Higher carbohydrate and lower protein content were observed in periods with more light. Carbohydrates produced during daylight were used for the protein synthesis at night, while the fatty acid content stayed constant during the day. The rate of carbohydrate loss at night was linearly related to the specific growth rate and therefore to the light history of the microalgae.