Microalgae have reported to be one of the most promising feedstock for biofuel production. To obtain a comprehensive and systematic overview of the current state of microalgal research, particularly microalgal biofuel research, we retrieved and analyzed manuscripts and patents related to this topic and published between 1900 and mid-2015. We found that there was a burst in microalgal biofuel research from 2006 to 2011 that significantly stimulated the development of microalgal biotechnology for the production of high value-added commodities and for environmental applications and microalgal mass culturing, in an attempt to make the entire process of biofuel production economically viable for industrialization. However, a lag in basic microalgal research has kept production costs high, resulting in a decline in investments, funding, and research efforts in the fields of microalgal biofuel production, microalgal biotechnology, and mass culturing since 2012. Based on a review of the challenges/problems of microalgae biofuel production and recent advances of their solution, the perspective view of the future R&D needs and trends were proposed. To bypass the price bottleneck of microalgae-based biofuel production, it has been proposed that energy-producing microalgal biotechnological applications be synergistically combined with microalgal biofuel production. Future investments and funding will most likely be directed toward basic studies that aim to elucidate the microorganisms' characteristics and toward the development of microalgal biotechnology and its environmental applications, which have potential economic and social benefits. This review represents a theoretical reference for both algal researchers and decision makers regarding the future directions of microalgal research, particularly that involving microalgal-based biofuel production. (C) 2015 Elsevier Ltd. All rights reserved.