A review on harvesting, oil extraction and biofuels production technologies from microalgae

Microalgae are receiving increasing attention worldwide as an alternative and renewable source for energy production. Through various conversion processes, microalgae can be used to produce many different kinds of biofuels, which include biodiesel, bio-syngas, bio-oil, bio-ethanol, and bio-hydrogen. However, large scale production of microalgal biofuels, via many available conversion techniques, faces a number of technical challenges which have made the current growth and development of the algal biofuel industry economically unviable. Therefore, in addition to algae culture and growth, it is also essential to develop cost-effective technologies for efficient biomass harvesting, lipid extraction and biofuels production. This review aims to collate and present an overview of current harvesting, oil extraction and biofuels production technologies from microalgae. Since much of the current studies on oil extraction are focused on biodiesel production from microalga, this study, apart from discussing the various biodiesel production techniques in the later sections, has also done a detailed discussion on the production techniques of other biofuels.