Cultivation of Chlorella sp. GD using piggery wastewater for biomass and lipid production

The development of a culture system for Chlorella sp. GD to efficiently produce biomass and oil for biodiesel production was investigated. Chlorella sp. GD was cultivated with 0%, 25%, 50%, 75% and 100% piggery wastewater (diluted by medium) at 300μmolm^-2s^-1, a 2% CO₂ aeration rate of 0.2vvm and 26±1°C; after a 10-day culture in batch cultures, the maximum specific growth rate and biomass productivity of the microalga obtained in 100% piggery wastewater were 0.839d^-1 and 0.681gL^-1d^-1, respectively. The highest lipid content and lipid productivity were 29.3% and 0.155gL^-1d^-1 at 25% wastewater, respectively. In semi-continuous cultures, the biomass and lipid productivities with 25-75% wastewater ratios were greater than 0.852 and 0.128gL^-1d^-1, respectively. These results show that Chlorella sp. GD grows efficiently in piggery wastewater, and that a stable growth performance was achieved for long-term microalgal cultivation in a semi-continuous culture.