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• Social changes on a global scale have challenged the nascent algal industry. • Drop-in fuel would be a new major target of algal lipid-based products. • Enhancing CO 2 fixing efficiency would be a major goal in outdoor cultivation. • An integrated refinery process is required for feasible whole cell utilization. Microalgae have been studied and tested for over 70 years. However, biodiesel, the prime target of the algal industry, has suffered from low competitiveness and current steps toward banning the internal combustion engine all over the world. Meanwhile, interest in reducing CO 2 emissions has grown as the world has witnessed disasters caused by global warming. In this situation, in order to maximize the benefits of the microalgal industry and surmount current limitations, new breakthroughs are being sought. First, drop-in fuel, mandatory for the aviation and maritime industries, has been discussed as a new product. Second, methods to secure stable and feasible outdoor cultivation focusing on CO 2 sequestration were investigated. Lastly, the need for an integrated refinery process to simultaneously produce multiple products has been discussed. While the merits of microalgae industry remain valid, further investigations into these new frontiers would put algal industry at the core of future bio-based economy. [ABSTRACT FROM AUTHOR]

[Display omitted] • Chlorella sp. ABC-001 showed the best growth and lipid yield with flue gas 10% CO 2. • Chlorella sp. ABC-001 was unaffected by NO but SO 2 severely inhibited cell growth. • Galdieria sulphuraria was adopted to remove SO 2 and enhance CO 2 and NO removal. • SO 2 removal is attributed to ionic interactions as well as assimilation by cells. • The dual-strain system showed stable growth under simulated flue gas supply. This study aims to propose a biological system that allows for direct utilization of flue gas for carbon dioxide capture and utilization by microalgae. The strain Chlorella sp. ABC-001 is employed for its high growth rate as well as lipid and carbohydrate content. Toxicity tests showed that cell growth was unaffected by NO, but the presence of SO 2 showed critical damage on cell growth. Hence, an extremophile alga, Galdieria sulphuraria 5587.1 was applied to build a dual-strain cultivation system to mitigate the effect of SO 2 toxicity and increase CO 2 capture efficiency. All SO 2 was removed by Galdieria culture and the system exhibited stable growth from a simulated flue gas stream containing CO 2 , NO and SO 2. Combined CO 2 biofixation rate of 793 mg/L/d and lipid productivity of 113 mg/L/d was achieved. The results showed that this new cultivation system is a promising alternative for reducing CO 2 emissions from power plants. [ABSTRACT FROM AUTHOR]