Comparison of autotrophic and mixotrophic cultivation of green microalgal for biodiesel production

The effects of autotrophic and mixotrophic growth on cell growth and lipid productivity of green microalgae Chodatella sp. were investigated. Carbon dioxide and piggery wastewater served as the carbon and nutrient sources, respectively, for autotrophic and mixotrophic growth. Appropriate doses of each source were found to be beneficial to biomass production. The cultures produced similar fatty acid compositions, which are suitable for biodiesel production. The specific growth rate, biomass production, and lipid productivity obtained with mixotrophic growth were 1.74, 14, and 5.6 times higher than those obtained with autotrophic growth, respectively. The mixotrophic cultivation simultaneously assimilated 99.7% ammonia nitrogen and 75.9% total phosphorus from piggery wastewater, which reduced the required nutrient for the culture of microalgae, thereby reducing the cost of biodiesel production.