Effects of Different Light Intensities and Nutrient Source on Growth Rate and Crude Fat Content in Chlorella vulgaris

Abstract

The aim of the present work was to study the effects of light intensities and culture medium prepared with two different types of feed on the growth rate and crude fat content of Chlorella vulgaris. Two different light wavelengths 796 μmol m-2 s-1 or 90% red light-emitting diodes (LEDs) and 129 μmolm-2s-1 (10% red LEDs) in combination with two different nutrient sources: 40/10 (40% crude protein and 10% crude lipid) and 32/6 diet as the nutrient source in the culture medium were employed to explore the effects of the treatments. From the experimental results, 90% red LEDs in combination with 40/10 diet exhibited the highest relative growth rate at the beginning of culture medium (day 1 and 3), while the 10% red LEDs yielded significantly higher growth rate at the end of culture medium (day 6). The light saturation could affect the growth of algae reared under 90% red LEDs, while gradual increase of light intensities in 10% red LEDs promotes better carrying capacity to support the growth of algae during the culture period. However, no significant differences in terms of crude fat content among all treatments. In comparing the growth rate and fat content, the use of 40/10 diet gave the most effective performance for the algae cultivation as the alternative feed source for aquaculture.