The feasibility of biodiesel production by microalgae using industrial wastewater

This study investigated nitrogen and phosphorus assimilation and lipid production of microalgae in industrial wastewater. Two native strains of freshwater microalgae were evaluated their biomass growth and lipid production in modified BBM medium. Chlamydomonas sp. TAI-2 had better biomass growth and higher lipid production than Desmodesmus sp.TAI-1. The optimal growth and lipid accumulation of Chlamydomonas sp. TAI-2 were tested under different nitrogen sources, nitrogen and CO2 concentrations and illumination period in modified BBM medium. The optimal CO2 aeration was 5% for Chlamydomonas sp. TAI-2 to achieve maximal lipid accumulation under continuous illumination. Using industrial wastewater as the medium, Chlamydomonas sp. TAI-2 could remove 100% NH4+-N (38.4 mg/L) and NO3−-N (3.1 mg/L) and 33% PO43−-P (44.7 mg/L) and accumulate the lipid up to 18.4%. Over 90% of total fatty acids were 14:0, 16:0, 16:1, 18:1, and 18:3 fatty acids, which could be utilized for biodiesel production.

► Chlamydomonas sp. TAI-2 was the optimal microalgae to produce biomass and lipid.
► Chlamydomonas sp. TAI-2 can utilize industrial wastewater to produce biodiesel.
► Chlamydomonas sp. TAI-2 removed 100% NH4+-N and NO3−-N and 33% P.
► Chlamydomonas sp. TAI-2 accumulated lipid up to 18.4 %.
► The composition of fatty acids was suitable for biodiesel production.