Examinando por Autor "Astals, Sergi"

Mostrando 1 - 2 de 2

Biodiesel and biogas production from Isochrysis galbana using dry and wet lipid extraction: A biorefinery approach
(Elsevier, 2020) Sánchez-Bayo, Alejandra; López-Chicharro, Daniel; Morales, Victoria; Espada, Juan José; Puyol, Daniel; Martínez, Fernando; Astals, Sergi; Vicente, Gemma; Bautista, Luis Fernando; Rodríguez, Rosalía
Wet lipid extraction combined with residual biomass anaerobic digestion are alternatives to reduce the overall energy consumption of biodiesel production from microalgae. Solvents with different polarities have been studied to assess dry and wet lipid extraction process from Isochrysis galbana microalga. Ethyl acetate (EA) and a chloroform:methanol (CM) mixture yielded the best lipid extraction results in the dry and wet route with suitable lipid compositions. Fatty acid methyl esters (FAMEs) conversion of dry and wet extracted lipids with these solvents was performed by using both homogeneous (H2SO4) and heterogeneous (resin CT 269) catalysts. FAME production from wet extracted lipids with the EA solvent using the CT-269 resin constitutes an advantageous process because it avoids the water elimination step, and the CT-269 is a heterogeneous commercial catalyst, readily to separate after reaction. Lipid-spent microalga was anaerobically digested, obtaining that waste biomass from the wet extraction with EA had the highest methane yield (310 mL CH4/g volatile solids (VS). Energy balance analysis for FAMEs production with EA solvent (wet route) and heterogeneous catalyst yielded an energy recovery of about 80% in terms of biodiesel and biogas. Therefore, this process constitutes a promising route under an energy-driven microalga biorefinery.
Pig slurry valorization by ammonia recovery, biogas upgrading and microbial protein production
(Elsevier, 2025-06-07) Prado de Nicolás, Amanda; Serra-Toro, Andreu; Ventura, Maria; Astals, Sergi; Dosta, Joan; Mas, Francesc; Segura, Yolanda; Melero, Juan A.; Martínez, Fernando; Puyol, Daniel
The management of pig slurry is associated with environmental concerns due to its high nitrogen content and greenhouse gas emissions. This work proposes a photobiorefinery concept integrating steam explosion pretreatment, ammonia recovery via gas-permeable membranes, anaerobic digestion, and microbial protein production using purple phototrophic bacteria (PPB). Pretreatment at 145 °C for 30 min led to 57% solubilization of organic matter and 29% reduction of total solids. More than 99% of ammoniacal nitrogen was recovered from the hydrolysate in less than 3 h. Methane production increased by up to 350% after pretreatment. The recovered nitrogen was used as a nutrient for PPB growth, enabling CO2 assimilation from biogas under photoautotrophic conditions and microbial protein production. The results demonstrate the feasibility of coupling thermal, biological, and phototrophic processes for the integrated valorization of pig slurry, with simultaneous recovery of energy and nutrients.