Utilization of gaseous emissions from a methanol plant for cultivation of <Emphasis Type="Italic">Acutodesmus obliquus</Emphasis>

This study aimed to culture the green alga Acutodesmus obliquus utilizing the gaseous emissions containing a high concentration of CO₂ (99.13 %) from a methanol plant and study the tolerance of microalgae. The effect of CO₂ concentration, aeration rate, inoculum concentration, intermittent sparging, and nitrogen sources on the growth of A. obliquus was examined. Acutodesmus obliquus also was cultivated in a 500-L pilot outdoor tubular photobioreactor (OTP) to advance the laboratory scale system to outdoor scale-up applications. The results showed that A. obliquus could tolerate high CO₂ concentrations of 50 %, and a maximum biomass of 0.935 g L^?1 (dry weight) was achieved at 20 % CO₂. An aeration rate of 500 mL min^?1, inoculum concentration (optical density at 680 nm OD₆₈₀]?=?0.3), and intermittent sparging of 10 min per 2 h enhanced growth to the optimum and influenced culture pH and photosynthesis. Urea as a nitrogen source was shown to be more beneficial to cell growth. A urea concentration of 0.3 g L^?1 and an N/P ratio of 15 led to maximum biomass accumulation thus enhancing the gaseous emission utilization efficiency. In conclusion, this work demonstrated that gaseous emissions containing high concentration of CO₂ from a methanol plant could be directly introduced into A. obliquus cultures and that A. obliquus was suitable well for large-scale outdoor cultivation in a tubular photobiorecator.