El-Sayed, A.B.1; M.A. Hassoub1

and M.A. Fathy2

1 Algal Biotechnology Unit, National Research Centre, Dokki, Cairo, Egypt.

2 Department of Animal Production, Fish Production Faculty of Agriculture, Al-Azhar University, Cairo, Egypt.


Cultures of Chlorella vulgaris were heterotrophically grown in fully transparent Plexi-Glass columns (14 L) and exposed to different light color (i.e.; yellow, green, blue and red) verses to and white light by covering the growth columns with fully transparency colored Nylon sheets with fixed light quantity (120µ.e).. Growth was performed with fully recommended media of BG-II. By the end of growth period (14 days). Growth parameters including dry weight, total chlorophyll and carotenes were daily assessed. Growth parameters were varied due to the used containers color type. Yellow and white colors enhanced dry weight accumulation, despite of inhibited chlorophyll accumulation. Maximum chlorophyll content was obtained by green light grown cultures followed by blue and red lights. Carotene was increased with all used colored light, but green light represented the lowest increase as compared with control culture at zero time. Concerning dry weight growth evaluation, maximum growth rate (µmax.) was found to be the highest with cultures exposed to yellow color followed by white color. On the contrast, a negative relationship was observed with cultures that exposed to red light. As for total chlorophyll, slight differences were observed. Regarding carotenes, green and red colors represented the lowest content, while white, yellow and blue colors had a little difference. Oil content was found to be slightly associated with carotenoids margin. White color container represented the maximum oil content following by the blue and yellow colors. Oil content was closely related to carotene content and maximum oil content was observed with yellow light grown alga (12.7), followed by 10.02 of blue light comparing with 9.4% of white light (control) and 9.34 of red light. The lowest oil content was observed with green lights that reach 8.22%.

Key words:
Chlorella vulgaris – light color – dry weight – total chlorophyll – carotene – oil content.