Microalgae Photobioreactor for Carbon Dioxide Fixation and Production of Biofuel Feedstock

Microalgae cultivation is considered fit to the concept of green economy, in which greenhouse gases (GHG's) mitigation and production of valuable substances is performed simultaneously. Carbon dioxide consumption by the algal cells reduces GHG's emission to the atmosphere, while biomass conversion to biofuel feedstock supports the concept of circular economy of microalgae cultivation process. In this study, Chlorella sp. was cultivated in a Multi Tubular Airlift Photobioreactor (MTAP) system with a total volume of about 600 L. The result of a thirteen days batch culture showed the ability of the system to fix 1.57 g CO₂ L^-1 day^-1. At the last day of experiment, 600 L MTAP showed biomass production of 0.35 g L^-1 and 18% oil from cell dry weight was observed. This research showed the ability of 600 L MTAP to absorb 942 g CO₂ and produce 37.8 g oil as biofuel feedstock. Compared to other experiments, percentage of oil in this experiment (18% from cell dry weight) was in the average range from other experiments (of about 10 – 40% from cell dry weight). However, this MTAP showed higher performance than other systems (mostly below 1 g CO₂ L^-1 day^-1) in CO₂ fixation rate.