Instalación y monitoreo de un fotobiorreactor para el cultivo autotrófico y la extracción de lípidos de microalgas Chlorella para la producción de biodiesel

摘要

Biodiesel from microalgae is a third generation biofuel. Third generation biofuels seek to shift the monoculture food crops fuel production. Some of the main advantages of biodiesel production from microalgae are small areas of culture, carbon dioxide capture from the air and oxygen production. The purpose of the project was to install and monitor a 10 L air-lift tubular photobioreactor (PBR) for autotrophic microalgae cultivation. Within the study, the performance of different strains was evaluated and determined that Chlorella sp. was the suitable one for the tubular photobioreactor set-up since it recorded optical density values greater than >2.000 in the wavelength of 600, 680 and 750 nm. The initial algal volume for the installation of the photobioreactor was 7.2 L with a sodium bicarbonate concentration of 0.10 g L-1. Improved harvesting conditions are proposed to increase the lipid content of the microalgae. An aeration flow of 3 L min-1 was provided to the PBR to assure complete mixing avoid sedimentation and cell disruption. A 2.5% daily volume extraction of the total work volume of the PBR and replacement with new medium is recommended to keep a constant growth of Chlorella sp. in the PBR. The lightning supply was provided by five white fluorescent cold 20 W lamps with 12 hours of light and darkness, respectively. The photosynthetically active radiation (PAR) corresponded to 124.13 μE m-2 s-1. The performance of the microalgae in the photobioreactor was monitored in terms of optical density (absorbance), algal density (g L-1) and lipid content (% w/w). Algal density varied between 0.04 and 1.45 g L-1. The greater optical density found was 2.92 (600 nm), 3.51 (680 nm) y 2.49 (750 nm). The highest lipid contents found was 20.23% w/w, sixty nine days after the installation and 33.53%w/w obtained a week after the dispersers were installed. The lipid productivity obtained was 0.414 g L-1 d-1.