Effects of some exogenous factors on growth and lipid accumulation of microalgae Haematococcus Pluvialis Flotow

Abstract

Haematococcus pluvialis cells were cultured in 500-ml bottles in two stages, each contained 250ml of liquid BB medium with aeration and an initial cell density of 4.3×103 cells/mL. All the experiments were carried out at 25 ± 3°C, and under the effect of fluorescence light (50µmol photon m-2s-1, 12 h/12 h light/dark cycle), except the experimentsunder the effect of LED lighting. After 7 weeks culture in BB medium (phase 1), some exogenous factors including LED light (intensity of 50μmol photon m-2s1): white, red (610 - 760nm) and blue (460 - 490nm) (treatment in 3 weeks, or 24 hours, or a 30-minute night interruption), heat shock (50oC during 1.5 or 2 hours, 7 ± 3oC during 2, 3, 4 or 6 hours, and 0 ± 2oC during 1.5 or 2 hours), heavy metals (Cu2+, Fe2+, Mg2+, Zn2 and NaCl at high concentrations during 3 days) were applied to study growth and lipid accumulation in Haematococcus pluvialis. After 10- week culture, the results showed that only red LED light treatment for 24 hours increased the biodiesel content, but reduced the fresh weight and the dry weight compared to the control (under the effect of fluorescent light). Treatment of 7 ± 3°C for 2 hours increased the biodiesel content and did insignificantly change the fresh weight, and reduced the dry weight. The treatments of Cu2+, Fe2+, Mg2+ and Zn2+ in 1,5 or double concentration not increase the biodiesel content. The treatment of 0.5% NaCl increased the biodiesel content, but reduced the fresh weight and the dry weight.

Keywords

• haematococcus pluvialis
• kim loại nặng
• sốc nhiệt độ
• tăng trưởng
• tích lũy lipid