Biological CO2 fixation using Chlorella vulgaris and its thermal characteristics through thermogravimetric analysis

• Published in: Bioprocess and biosystems engineering 2016-11, Vol.39 (11), p.1651-1658
• Main Authors: Razzak, Shaikh A., Ali, Saad Aldin M., Hossain, Mohammad M., Mouanda, Alexis Nzila
• Format: Article
• Language: English
• Subjects: Algae; Biomass; Bioreactors; Biotechnology; Carbon dioxide; Carbon Dioxide - metabolism; Carbon dioxide fixation; Carbon sequestration; Chemistry; Chemistry and Materials Science; Chlorella vulgaris - growth & development; Environmental Engineering/Biotechnology; Food Science; Industrial and Production Engineering; Industrial Chemistry/Chemical Engineering; Kinetics; Membrane reactors; Microalgae; Models, Biological; Original Paper; Reactors; Thermogravimetric analysis
• ISSN: 1615-7591; 1615-7605
• DOI: 10.1007/s00449-016-1640-7

The present research is focused on cultivation of microalgae strain Chlorella vulgaris for bio-fixation of CO 2 coupled with biomass production. In this regard, a single semi-batch vertical tubular photobioreactor and four similar photobioreactors in series have been employed. The concentration of CO 2 in the feed stream was varied from 2 to 12 % (v/v) by adjusting CO 2 to air ratio. The amount of CO 2 capture and algae growth were monitored by measuring decrease of CO 2 concentration in the gas phase, microalgal cell density, and algal biomass production rate. The results show that 4 % CO 2 gives maximum amount of biomass (0.9 g L −1 ) and productivity (0.118 g L −1  day −1 ) of C. vulgaris in a single reactor. In series reactors, average productivity per reactor found to be 0.078 g L −1  day −1 . The maximum CO 2 uptake for single reactor also found with 4 % CO 2, and it is around 0.2 g L −1  day −1 . In series reactors, average CO 2 uptake is 0.13 g L −1  day −1 per reactor. TOC analysis shows that the carbon content of the produced biomass is around 40.67 % of total weight. The thermochemical characteristics of the cultivated C. vulgaris samples were analyzed in the presence of air. All samples burn above 200 °C and the combustion rate become faster at around 600 °C. Almost 98 wt% of the produced biomass is combustible in this range.