초록
<P><B>Highlights</B></P><P>► Effects of medium and growth conditions on microalgal lipid production were studied. ► Mixotrophic growth was preferable for lipid production of <I>Chlorella vulgaris</I> ESP-31. ► The highest lipid content and productivity were 53% and 144mg/l/d, respectively. ► Composition of the microalgal lipids is suitable for biodiesel synthesis.</P> <P><B>Abstract</B></P><P>The growth and lipid productivity of an isolated microalga <I>Chlorella vulgaris</I> ESP-31 were investigated under different media and cultivation conditions, including phototrophic growth (NaHCO<SUB>3</SUB> or CO<SUB>2</SUB>, with light), heterotrophic growth (glucose, without light), photoheterotrophic growth (glucose, with light) and mixotrophic growth (glucose and CO<SUB>2</SUB>, with light). <I>C. vulgaris</I> ESP-31 preferred to grow under phototrophic (CO<SUB>2</SUB>), 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.</P>