Initial study of lipid accumulation in green algal Haematococcus pluvialis Flotow cultured in liquid Bold’s Basal medium aerated

Abstract

The fresh green algal Haematococcus pluvialis Flotow was proved to be the starting material for the production of biofuel, high lipid content along with astaxanthin, a high value colorant. In this study, lipid accumulation in H. pluvialis cultured in liquid Bold’s Basal medium aerated was investigated for a period of 12 weeks. Lipid accumulation was evaluated through the expression of two genes: BC (biotin carboxylase, initial gene) and FATA (acyl-acyl carrier protein thioesterase, end gene) in the process of fatty acid biosynthesis with Real-time RT-PCR, lipid determination by Nile Red and biodiesel quantifying by transesterification. The results showed that the expression of two BC and FATA genes was recorded at all weeks of culture. However, the expression of BC and FATA genes increased gradually from the week 9 (1.3, 4.1, respectively) to week 11 (1.7, 30.9, respectively). Meanwhile, yellow fluorescence in the microalgal cells showed that lipid appeared from week 6 to week 12. The obtained biodiesel increased slowly from week 8 (0.036 mg/mL) to week 12 (0.041 mg/mL). At week 11, the expression values of both BC gene (1.7) and FATA gene (30.9) were maximized, leading to the highest biodiesel content at the week 12.