Carbon dioxide (CO2) biofixation by microalgae and its potential for biorefinery and biofuel production.
Carbon dioxide (CO2) using biological process is one of the promising approaches for CO2capture and storage. Recently, biological sequestration using microalgae has gained many interest due to its capability to utilize CO2as carbon source and biomass produced can be used as a feedstock for other value added product for instance biofuel and chemicals. In this study, the CO2biofixation by two microalgae species, Chlorella sp. and Tetraselmis suecica was investigated using different elevated CO2concentration. The effect of CO2concentration on microalgae growth kinetic, biofixation and its chemical composition were determined using 0.04, 5, 15 and 30% CO2. The variation of initial pH value and its relationship on CO2concentration toward cultivation medium was also investigated. The present study indicated that both microalgae displayed different tolerance toward CO2concentration. The maximum biomass production and biofixation for Chlorella sp. of 0.64gL-1and 96.89mgL-1d-1was obtained when the cultivation was carried out using 5 and 15% CO2,respectively. In contrast, the maximum biomass production and CO2biofixation for T. suecica of 0.72gL-1and 111.26mgL-1d-1were obtained from cultivation using 15 and 5% CO2. The pH value for the cultivation medium using CO2was between 7.5 and 9, which is favorable for microalgal growth. The potential of biomass obtained from the cultivation as a biorefinery feedstock was also evaluated. An anaerobic fermentation of the microalgae biomass by bacteria Clostridium saccharoperbutylacenaticum N1-4 produced various type of value added product such as organic acid and solvent. Approximately 0.27 and 0.90gL-1of organic acid, which corresponding to acetic and butyric acid were produced from the fermentation of Chlorella sp. and T. suecica biomass. Overall, this study suggests that Chlorella sp. and T. suecica are efficient microorganism that can be used for CO2biofixation and as a feedstock for chemical production.
Bioprocess Technology Division, School of Industrial Technology, Universiti Sains Malaysia (USM), Penang, Malaysia. Electronic address: asyrafkassim@usm.my.
Mohd Asyraf
MA
Kassim
Bioprocess Technology Division, School of Industrial Technology, Universiti Sains Malaysia (USM), Penang, Malaysia.
Tan Keang
TK
Meng
D056804:Biofuels; D018533:Biomass; D002245:Carbon Dioxide / Q000737:chemistry*; D002708:Chlorella / Q000378:metabolism; D000460:Chlorophyta / Q000378:metabolism; D058086:Microalgae / Q000378:metabolism*
D056804:Biofuels; D002245:Carbon Dioxide
Biomass; CO(2) biofixation; Elevated condition; Fermentation; Microalgae