title: Effect of solar radiation on the lipid characterization of biomass cultivated in high-rate algal ponds using domestic sewage.
abstract: The objective of this paper is to compare the lipid content and composition ofbiomass produced by a consortium of microalgae and bacteria, cultivated under different solar radiation intensities and tropical conditions in pilot-scale high-rate ponds (HRPs) using domestic sewage as culture medium. The treatment system consisted of an upflow anaerobic sludge blanket reactor followed by UV disinfection and six HRPs covered with shading screens that blocked 9%, 18%, 30%, 60% and 80% of the solar radiation. The total lipid content does not vary significantly among the units, showing a medium value of 9.5%. The results show that blocking over 30% of the solar radiation has a negative effect on the lipid productivity. The units with no shading and with 30% and 60% of solar radiation blocking have statistically significant lipid productivities, varying from 0.92 to 0.96 gm(-2) day(-1). Besides radiation, other variables such as volatile suspended solids and chlorophyll-a are able to explain the lipid accumulation. The lipid profile has a predominance of C16, C18:1 and C18:3 acids. The unsaturation of fatty acids increases with the reduction in solar radiation. On the other hand, the effect of polyunsaturation is not observed, which is probably due to the presence of a complex and diverse biomass.
authors.forename: Paula Peixoto
authors.initials: PP
authors.lastname: Assemany
authors.forename: Maria Lúcia
authors.initials: ML
authors.lastname: Calijuri
authors.forename: Anibal da Fonseca
authors.initials: Ada F
authors.lastname: Santiago
authors.forename: Eduardo de Aguiar
authors.initials: Ede A
authors.lastname: do Couto
authors.forename: Mauricio de Oliveira
authors.initials: Mde O
authors.lastname: Leite
authors.forename: Jose Jovanny Bermudez
authors.initials: JJ
authors.lastname: Sierra
mesh_terms: D001419:Bacteria / Q000737:chemistry / Q000378:metabolism; D056804:Biofuels; D018533:Biomass; D019149:Bioreactors; D006863:Hydrogen-Ion Concentration; D050356:Lipid Metabolism / Q000528:radiation effects*; D008055:Lipids / Q000032:analysis / Q000737:chemistry; D058086:Microalgae / Q000737:chemistry / Q000378:metabolism; D010100:Oxygen; D010839:Phytoplankton; D012722:Sewage; D012993:Solar Energy; D013696:Temperature
chemical_list: D056804:Biofuels; D008055:Lipids; D012722:Sewage; D010100:Oxygen