Iron uptake mechanism in the chrysophyte microalga Dinobryon

Strategy study on enhancing lipid productivity of filamentous oleaginous microalgae Tribonema

Filamentous microalgae Tribonema is promising for biodiesel production in terms of high lipid content, easy harvesting and good contamination tolerance. As high lipid productivity is a key basis, several methods including different culture medium, phosphorus, iron and CO2 inductions were tested to enhance lipid productivity in Tribonema minus. T. minus subjected to BG11-freshwater medium achieved a favorable lipid productivity of 216.18mgL(-1)d(-1), much higher than those in other culture medium (BG11-S, Kuhl, f/2, f, 2f, BBM, ASW and ES). Secondly, the optimal phosphorus, iron and CO2 concentrations for high lipid productivity of T. minus were obtained, respectively. Finally, the cells of T. minus grown in optimized BG11 medium containing 80mgL(-1) KH2PO4 and 6mgL(-1) FeC6H5O7·NH4OH with 2% CO2 achieved a lipid productivity of 384.67mgL(-1)d(-1), representing a 1.56-fold increase from the control. Therefore, the strategy to enhance lipid productivity of T. minus was successfully proposed.

Enhanced biomass production, lipid yield and sedimentation efficiency by iron ion

Effects of Fe(3+) on the biomass production, lipid accumulation of Monoraphidium sp. FXY-10 were investigated. Further residual Fe(3+) in the culture medium on the sedimentation efficiency have been also studied. The biomass and lipid productivity of microalgae exhibited an increasing tendency with the concentrations of iron ion augmenting. 150 μM iron ion added into the culture medium result in highest DCW at 1.42 g L(-1) while the maximum lipid productivity of 10.71 mg L(-1) d(-1) were obtained at 50 μM. The results showed that appropriate concentrations of iron ion was beneficial for biomass production and lipid accumulation but higher concentration of that will be more in favor of the sedimentation efficiency of Monoraphidium sp. FXY-10.