Effects of cultivation conditions and media composition on cell growth and lipid productivity of indigenous microalga Chlorella vulgaris ESP-31

摘要

The growth and lipid productivity of an isolated microalga Chlorella vulgaris ESP-31 were investigated under different media and cultivation conditions, including phototrophic growth (NaHCO _3 or CO _2, with light), heterotrophic growth (glucose, without light), photoheterotrophic growth (glucose, with light) and mixotrophic growth (glucose and CO _2, with light). C. vulgaris ESP-31 preferred to grow under phototrophic (CO _2), photoheterotrophic and mixotrophic conditions on nitrogen-rich medium (i.e., Basal medium and Modified Bristol's medium), reaching a biomass concentration of 2-5g/l. The growth on nitrogen-limiting MBL medium resulted in higher lipid accumulation (20-53%) but slower growth rate. Higher lipid content (40-53%) and higher lipid productivity (67-144mg/l/d) were obtained under mixotrophic cultivation with all the culture media used. The fatty acid composition of the microalgal lipid comprises over 60-68% of saturated fatty acids (i.e., palmitic acid (C16:0), stearic acid (C18:0)) and monounsaturated acids (i.e., oleic acid (C18:1)). This lipid composition is suitable for biodiesel production.