Cosa

Appl Microbiol Biotechnol (2008) 79:707–718

DOI 10.1007/s00253-008-1518-y

MINI-REVIEW

CO2 bio-mitigation using microalgae

Bei Wang & Yanqun Li & Nan Wu & Christopher Q. Lan

Received: 1 March 2008 / Revised: 20 April 2008 / Accepted: 21 April 2008 / Published online: 16 May 2008

# Springer-Verlag Berlin Heidelberg 2008

Abstract Microalgae are a group of unicellular or simple

multicellular photosynthetic microorganisms that can fix

CO2 efficiently from different sources, including the

atmosphere, industrial exhaust gases, and soluble carbonate

salts. Combination of CO2 fixation, biofuel production, and

wastewater treatment may provide a very promising

alternative to current CO2 mitigation strategies.

Keywords Microalga . CO2 mitigation . Biofuel .

Biodiesel . Biomass conversion

Introduction

Due to the fast-growing concern about global warming,

which can be attributed primarily to the elevated CO2 level

in the atmosphere (Kondili and Kaldellis 2007; RomanLeshkov et al. 2007), the United Nations promoted the

Kyoto Protocol (1997) with the objective of reducing

greenhouse gases by 5.2% on the basis of the emission in

1990, and more than 170 countries have ratified the

protocol (Gutierrez et al. 2008). Various CO2 mitigation

strategies have been investigated, which can be generally

classified into two categories: (1) chemical reaction-based

approaches and (2) biological CO2 mitigation. A popular

chemical reaction-based CO2 mitigation approach is achieved

by cyclic carbonation/de-carbonation reactions in which

gaseous CO2 reacts with solid metal oxide (represented by

B. Wang : Y. Li : N. Wu : C. Q. Lan (*)

Department of Chemical Engineering, The University of Ottawa,

161 Louis Pasteur St.,

Ottawa, ON, Canada K1N 6N5

e-mail: Christopher.Lan@uottawa.ca

MO) to yield metal carbonate (MCO3; Gupta and Fan 2002).

The reaction can be represented by Eq. 1.

MO þ CO2 ! MCO3

ð1Þ

Once the metal oxide reaches its ultimate...