Effects of Temperature on Growth and Biochemical Composition of Arctic Pseudanabaena sp. and Tropical Synechococcus sp.

This study examines the effect of temperature on the growth and biochemical composition of two cyanobacteria: Pseudanabaena sp. from the Arctic region and Synechococcus sp. from a tropical region. Cyanobacterial isolates were cultivated under three different temperatures: 4 +/- 2 degrees C, 15 +/- 2 degrees C and 25 +/- 2 degrees C. The growth rate of Pseudanabaena sp. at 4 +/- 2 degrees C, 15 +/- 2 degrees C and 25 +/- 2 degrees C was 1.61 day-1, 1.62 day-1 and 1.53 day-1, while the doubling time was 0.11, 0.18 and 0.08 days, respectively. The growth rate of Synechococcus sp. was slightly lower. At 4 +/- 2 degrees C, 15 +/- 2 degrees C and 25 +/- 2 degrees C, the growth rate was recorded at 0.65 day-1, 0.94 day-1 and 1.06 day-1, while the doubling time was 0.003, 0.07 and 0.25 days, respectively. Total carbohydrate for Pseudanabaena sp. at 4 +/- 2 degrees C, 15 +/- 2 degrees C and 25 +/- 2 degrees C was 207.16 +/- 10.03 mg/L, 329.57 +/- 189.65 mg/L and 63.32 +/- 41.02 mg/L, respectively. At the same temperature, the total carbohydrate for Synechococcus sp. was 269.44 +/- 81.29 mg/L, 321.15 +/- 73.31 mg/L and 1556.84 +/- 243.38 mg/L, respectively. It illustrates higher total carbohydrate in Synechococcus sp. compared to Pseudanabaena sp. At 4 +/- 2 degrees C, 15 +/- 2 degrees C and 25 +/- 2 degrees C, total protein for Pseudanabaena sp. was recorded as 5.59 +/- 0.09 mg/L, 5.23 +/- 0.21 mg/L, and 4.34 +/- 0.47 mg/L. Meanwhile, for Synechococcus sp., total protein recorded at temperatures 4 +/- 2 degrees C, 15 +/- 2 degrees C and 25 +/- 2 degrees C was 0.47 +/- 0.01 mg/L, 0.45 +/- 0.01 mg/L and 0.39 +/- 0.05 mg/L, respectively. This study shows that the growth rate and biochemical composition of Arctic Pseudanabaena sp. and tropical Synechococcus sp. were influenced by different temperature levels.