PERTANIKA JOURNAL OF TROPICAL AGRICULTURAL SCIENCE

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°C, 15±2°C and 25±2°C. The growth rate of Pseudanabaena sp. at 4±2°C, 15±2°C and 25±2°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°C, 15±2°C and 25±2°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°C, 15±2°C and 25±2°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°C, 15±2°C and 25±2°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°C, 15±2°C and 25±2°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.