Processing of lipid-enriched microalgae Chlorella biomass into biofuels and value-added chemicals

Replacement of non-renewable energy sources by renewable fuels may solve the environmental problems associated with the climate change and energy crisis. Microalgae are widely employed sources of biofuels, which have attracted huge attention in recent years due to their great productivity with lipid content. Among micro- algae species, Chlorella is one of the most attractive and commercially available algae species for producing biofuels and other valuable products owing to its fast growth, easy cultivation, and high lipid content under certain cultivation conditions. However, to date, researchers are faced with numerous problems related to the economic feasibility of Chlorella biomass processing technology. A significant contribution to the profitability of Chlorella biomass processing is made by the creation of competitive biofuels and value-added products, which are not inferior in their properties to prepared by conventional routes. This critical review presents a detailed evaluation of current advances over the past 10 years in fundamental and pragmatic research on lipid-enriched microalgae Chlorella for various applications, including transesterification to biodiesel and thermochemical conversion to bio-oil. This review also particularly highlights the promising directions in fatty acid methyl esters applications other than a fuel that could be taken into account for further research. Moreover, challenges and opportunities are considered into developing new technologies with high profitability and possible future commercialization.