The effect of pH, dark - light cycle and light colour on the chlorophyll and carotenoid production of Spirulina sp.

Abstract

Spirulina sp., multicellular filament algae, is helically coiled. This is a rich nutrition microalgae with protein, carbohydrate, vitamin, chlorophyll and carotenoid. Many researches and applications of Spirulina sp. have been studied by interested scientists, especially, pigment production. The purpose of this research was determination the effect of pH, dark – light cycle and light colour on the growth and pigment production of Spirulina sp. The results showed that pH 9, white light and continuous illumination 24/24 hours were appropriate conditions for biomass increasing, chlorophyll a, chlorophyll b and carotenoid production in Spirulina sp. At pH 9, biomass and carotenoid were highest in day 8 (0.16g/ 50mL and 1.43 ?g/mL, respectively). The highest production of chlorophyll a and chlorophyll b were collected in day 12 (2.72 ?g/mL and 3.35 ?g/mL, respectively). The growth ofSpirulina sp. was slow at green colour and limited at red colour. Compared to 12/24 hour illumination, growing algae under continuous illumination 24/24 hour was higher 1.08 times in biomass, 2.36 times in chlorophyll a, 1.2 times in chlorophyll b and 1.7 times in carotenoid content. When white light was applied, continuous illumination 24/24 hour and aeration, pH remained from 10 to 10.8, then decreased in day 16 and 20 and no significant differences between treatments during the experiment. Besides, Spirulina ‘s shape recovered quickly in appropriate conditions.