Carotenoids from tropical microalgae, Chlorella sp; determination of the effects of carotenoids on known pathogens

Abstract

A marine microalgae which is local Chlorella sp has been used in this study. Carotenoids that were obtained from this microalgae were used in various experiment in this project. Firstly, the percentage of total carotenoid per dry weight of Chlorella sp was 47.6% in 30L culture of microalgae. The production of carotenoid in this microalgae was done by using the nutrient starvation stress. When the microalgae were in stress condition, they will produce more carotenoid. Then, the DPPH test was held where the EC50 for this experiment was 58.63%. The EC50 was obtained to know the effective concentration at 50 percent for this Chlorella sp crude. If the effective concentration is higher than 50 percent, the crude has more antioxidant properties. The MTT test was done to MCF-7 and normal cell line. The LC50 which is lethal concentration at 50 percent were obtained. MCF-7 and normal cell line show a same concentration which is 0.25mg/ml at LC50. This crude can kill MCF-7 and it also can kill the normal cell, which is mean that this crude was toxic to use to human. The effect on known pathogen had been done using the Chlorella sp crude. E.coli and Klebsiella sp show probiotic reaction towards the crude, while P.aeruginosa shows inhibition reaction. Pathogen Salmonella sp and B.cereus was neutral which is mean no reaction had been seen. Most of the pathogen from gram­ negative pathogen resistant to many antibiotic that are effective against gram-positive bacteria.