Investigation of Different Light Sources and Cycles on the Growth and Lipid Production Mechanisms for Various Microalgae Species

Microalgae are used for various purposes, mainly as food supplements by people because of the protein, carbohydrate, fatty acids, vitamins, minerals, pigments, and many other compounds they contain. Efforts to utilize microalgae as a raw material for the production of biodiesel are increasing, especially in European countries. In this study, the effects of different light sources (Led, Incandescent, Green, Yellow, Blue, Red)  and cycles 10:14,12:12,14:10,0:24(night: day) on the growth and lipid production of Chlorella protothecoides and Chlorella  ESP-6 species were investigated. All of the experiments were conducted in 100ml flasks that contained culture medium BG 11.  The results showed that Chlorella ESP-6 reached 0.25 gdw/L maximum cell concentration under the incandescent lamp (3.16 Klux), whereas 0.39 gdw/L maximum cell concentration under the 14:10 light cycle. Chlorella protothecoides attained a maximum cell concentration of 0.18 gdw/L, and 0.26 gdw/L under the led lamp (3 Klux) and 0:24 light cycle respectively. No significant effects of different light sources on the microorganism lipid content were observed. The average lipid content of microorganisms each for applied light intensity was determined to be 45% and 17% for Chlorella protothecoides and Chlorella ESP-6 respectively. On the other hand, with the effect of the light cycles on the microorganism lipid content, it was seen that the lightness phase for Chlorella ESP-6 increased considerably. There was no significant effect on Chlorella protothecoides. The highest lipid contents were determined as 17% and 48% for both microorganisms respectively.