Energies, Vol. 18, Pages 6559: Fertilizer-Derived Low-Cost Culture Medium for Microalgae and Biofuel Production from Hydrothermal Liquefaction
Energies doi: 10.3390/en18246559
Authors:
Alejandra M. Miranda
Fabian Hernandez-Tenorio
Gabriel J. Vargas
David Ocampo
Alex A. Sáez
Microalgae have been characterized as an effective raw material for obtaining bioproducts from a biorefinery approach. However, production costs limit the large-scale production of microalgae, which makes these processes uncompetitive in the market. Therefore, in the present work, different agricultural fertilizers were evaluated as low-cost culture media for microalgae growth and the use of the biomass for biocrude production. The tests were carried out in three phases: phase I, Laboratory scale 1 L Erlenmeyer (Boeco, Hamburg, Germany) and phase II–III Pilot scale with cylindrical photobioreactors (PBRs) (Atb services S.A.S, Medellin, Colombia) with a capacity of 20 L. In phase I, four commercial fertilizers Crecilizer® (C), Florilizer® (F) (Fertilizer, Bogota, Colombia), AcuaLeaf Macros® (Ma), and AcuaLeaf Micros® (Mi) (Deacua, Medellin, Colombia) were tested separately and in combination (C + Ma, F + M, and Ma + Mi). The most effective treatments (C and F) in phase I were chosen for scale-up during phase II. In phase III, the concentration of the best treatment from phase II was increased. The biomass obtained from the best phase III treatment showed a cultivation medium cost 50% lower than the biomass obtained using Bold’s Basal Medium (BBM). Following each treatment, the harvested biomass was processed via hydrothermal liquefaction (HTL) to yield biocrude. The reduction in culture medium cost contributed to an estimated 40% decrease in the relative biocrude yield cost.