title: Ammonia inhibition on Arthrospira platensis in relation to the initial biomass density and pH.
abstract: In this study the combined effect of total ammoniacal nitrogen (TAN) concentration, initial biomass density and initial pH of the cultivation medium on growth of Arthrospira platensis was studied. The results indicate that TAN inhibition in relation to the initial biomass in unregulated pH cultures is neither a clearly biomass-independent nor biomass-dependent phenomenon. However, low biomass densities are more susceptible to ammonia inhibition than higher biomass densities. Higher biomass densities seems to mitigate ammonia inhibition through rapider assimilation of TAN. In all cases studied the growth rates were lower compared to the cultures with nitrate as nitrogen source. It was observed that at low TAN concentration, although no ammonia inhibition occured the growth rates were decreased due to nitrogen limitation. Low TAN concentration triggered the accumulation of carbohydrates affecting thus significantly the biomass composition. Ammonia losses from the cultivation system were also determined. Ammonia losses ranged between 17% and 80%.
authors.affiliation: Department of Natural Resources Management and Agricultural Engineering, Agricultural University of Athens, Iera Odos 75, 11855 Athens, Greece. Electronic address: markoug@aua.gr.
authors.forename: Giorgos
authors.initials: G
authors.lastname: Markou
authors.affiliation: Laboratory Aquatic Biology, KU Leuven Kulak, E. Sabbelaan 53, 8500 Kortrijk, Belgium.
authors.forename: Dries
authors.initials: D
authors.lastname: Vandamme
authors.affiliation: Laboratory Aquatic Biology, KU Leuven Kulak, E. Sabbelaan 53, 8500 Kortrijk, Belgium.
authors.forename: Koenraad
authors.initials: K
authors.lastname: Muylaert
mesh_terms: D000641:Ammonia / Q000633:toxicity*; D056804:Biofuels; D018533:Biomass; D019149:Bioreactors; D018929:Cell Culture Techniques; D006863:Hydrogen-Ion Concentration; D013053:Spectrophotometry; D053545:Spirulina / Q000187:drug effects* / Q000254:growth & development*
chemical_list: D056804:Biofuels; D000641:Ammonia
keywords: Ammonia inhibition; Ammonia losses; Biomass; Microalgae; Nutrients