Effects of Cultivation Conditions and Media Compositions on Lipid Productivity of Native Microalga <i>Chlorella vulgaris</i> U3-3

Abstract

A native microalgae strain Chlorella vulgaris U3-3from Baimaxueshan Yunnan province has been isolated and identified as a potential feedstock for biodiesel production. The biomass production, lipid productivity, and fatty acid compositions of U3-3 are investigated and compared under phototrophic, heterotrophic and mixotrophic conditions with various media. U3-3 under phototrophic growth on BG11 medium shows higher cellular lipid content (44.6%) than those under heterotrophic and mixotrophic conditions. And U3-3 display its higher biomass production (5.55g/L) than those under phototrophic and heterotrophic conditions growing on optimized medium with supply 35g/L glucose under mixotrophic condition. However, Chlorella vulgaris U3-3 growing under heterotrophic condition with optimized medium of supply 35g/L glucose exhibited more than 7.26-fold and 1.05-fold increase in lipid productivity compared with that under phototrophic and mixotrophic conditions. Moreover, Chlorella vulgaris U3-3 has suitable fatty acid compositions with high saturated acid contents (28.76%) and favorable degree of unsaturation (92.86) growing under heterotrophic condition with optimized medium of supply 35g/L glucose, suggesting its potential as a biodiesel feedstock on this cultivation condition and medium composition.