Optimisation and growth kinetic analysis of Microalgae, Arthrospira platensis in 2-L Photobioreactors

Abstract

In recent years, photoautotrophic microalgae are widely recognised due to their diverse yet significant natural values, particularly in healthcare, including pharmaceuticals, cosmetics and feedstock industries. One of the most exploited blue-green microalgae, Arthrospira sp. has been addressed as a potent superfood. However, the microalgal mass-production requires suitable inoculum strain and controlled cultivation conditions for enhanced growth performance. Hence, this study aimed to maximise biomass of Arthrospira platensis chosen strain in a 2 litres indoor photobioreactor under three different parameters which were aeration rate, light intensity and pH of the medium. In the present study, a comparative study of growth performance between helical (S1) and straight form (S2) of A. platensis was conducted and the results revealed that morphological differences did not affect growth performances. Meanwhile, the optimisation based on the parameters studied shows that cultivation of A. platensis with aeration of 0.5 L/min and medium of pH 9.0 yielded the highest biomass production which were 1.500 ± 0.049 g/L. Under different light intensity, A. platensis produced the highest biomass and maximum specific growth rate of 1.142 ± 0.037 g/L and 0.716 ± 0.018 1/day, respectively when cultivated under irradiance of 6000 Lux. In conclusion, compared to before optimisation, biomass and maximum specific growth rate after optimisation was 137% and 24% increased, respectively.