title: Increased microalgae growth and nutrient removal using balanced N:P ratio in wastewater.
abstract: Microalgal cultivation using wastewater is now regarded as essential for biodiesel production, as two goals can be achieved simultaneously; that is, nutrient removal efficiency and biomass production. Therefore, this study examined the effects of carbon sources, the N:P ratio, and the hydraulic retention time (HRT) to identify the optimal conditions for nutrient removal efficiency and biomass production. The effluent from a 2nd lagoon was used to cultivate microalgae. Whereas the algal species diversity and lipid content increased with a longer HRT, the algal biomass productivity decreased. Different carbon sources also affected the algal species composition. Diatoms were dominant with an increased pH when bicarbonate was supplied. However, 2% CO(2) gas led to a lower pH and the dominance of filamentous green algae with a much lower biomass productivity. Among the experiments, the highest chlorophyll-a concentration and lipid productivity were obtained with the addition of phosphate up to 0.5 mg/l P, since phosphorus was in short supply compared with nitrogen. The N and P removal efficiencies were also higher with a balanced N:P ratio, based on the addition of phosphate. Thus, optimizing the N:P ratio for the dominant algae could be critical in attaining higher algal growth, lipid productivity, and nutrient removal efficiency.
authors: Environmental Biotechnology Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-806, Korea.
authors: Seung-Hoon
authors: SH
authors: Lee
authors: Chi-Yong
authors: CY
authors: Ahn
authors: Beom-Ho
authors: BH
authors: Jo
authors: Sang-Ah
authors: SA
authors: Lee
authors: Ji-Yeon
authors: JY
authors: Park
authors: Kwang-Guk
authors: KG
authors: An
authors: Hee-Mock
authors: HM
authors: Oh
mesh_terms: D044822:Biodiversity; D056804:Biofuels; D018533:Biomass; D058086:Microalgae / Q000254:growth & development*; D009584:Nitrogen / Q000378:metabolism*; D009930:Organic Chemicals / Q000378:metabolism*; D010758:Phosphorus / Q000378:metabolism*; D062065:Wastewater / Q000737:chemistry* / Q000382:microbiology*
chemical_list: D056804:Biofuels; D009584:Nitrogen; D009930:Organic Chemicals; D010758:Phosphorus; D062065:Wastewater