ISSN 2756-3391
African Journal of Parasitology Research ISSN 2756-3391 Vol. 10 (4), pp. 001-012, April, 2022. © International Scholars Journals
Full Length Research Paper
The effects of nutritional restriction on neutral lipid accumulation in Chlamydomonas and Chlorella
Xiaodong Deng1, Xiaowen Fei1,2* and Yajun Li1
1Key Laboratory of Tropical Crop Biotechnology, Ministry of Agriculture, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Science, Haikou 571101, China.
2Department of Biochemistry, Hainan Medical College, Haikou 571101, China.
Accepted 12 January, 2021
Abstract
Under nutrient starvation conditions, many microalgae are known to accumulate triacylglycerols (TAG) that can be used for biodiesel production. However, few studies have been performed to analyze the effect of deficiency in nutrient elements such as sulfur, phosphorus, potassium, iron, magnesium and calcium on oil production, particularly in Chlamydomonas and Chlorella. In this study, we investigated lipid content of Chlamydomonas reinhaditti CC124 and Chlorella vulgaris Y-019 grown in TAP, HSM, BG11, SE lacking optimal concentrations of these elements. Our results showed that, in high carbon HSM and TAP media, N and S starvation led to significant increase in cellular lipid content in both microalgae species. In addition, C. reinhaditti grown in TAP media without P, Fe, K, Ca or Mg or in HSM media without K, Ca or Mg also accumulated detectably higher neutral lipids. In contrast, in C. vulgaris, such accumulation was observed only in Mg-free and Fe-free HSM media. In low carbon SE and BG11 media, N starvation resulted in a moderate increase in the lipids content both in C. reinhaditti and C. vulgaris. On the other hand, P, S, K, Ca or Mg deficiency promoted neutral lipids accumulation in C. vulgaris. Finally, we analyzed and discussed the relationships among cell growth rate, lipid accumulation and nitrogen concentrations in C. reinhaditti.
Key words: Nutrient limitation, lipid accumulation, nitrogen, sulfur, phosphorus, potassium, iron, magnesium, calcium.