Determination of Microalgal Lipid Content and Fatty Acid for Biofuel Production

Abstract

Biofuels produced from microalgal biomass have received growing worldwide recognition as promising alternatives to conventional petroleum-derived fuels. Among the processes involved, the downstream refinement process for the extraction of lipids from biomass greatly influences the sustainability and efficiency of the entire biofuel system. This review summarizes and compares the current techniques for the extraction and measurement of microalgal lipids, including the gravimetric methods using organic solvents, CO2-based solvents, ionic liquids and switchable solvents, Nile red lipid visualization method, sulfo-phospho-vanillin method, and the thin-layer chromatography method. Each method has its own competitive advantages and disadvantages. For example, the organic solvents-based gravimetric method is mostly used and frequently employed as a reference standard to validate other methods, but it requires large amounts of samples and is time-consuming and expensive to recover solvents also with low selectivity towards desired products. The pretreatment approaches which aimed to disrupt cells and support subsequent lipid extraction through bead beating, microwave, ultrasonication, chemical methods, and enzymatic disruption are also introduced. Moreover, the principles and procedures for the production and quantification of fatty acids are finally described in detail, involving the preparation of fatty acid methyl esters and their quantification and composition analysis by gas chromatography.

Nutritional Potential and Toxicological Evaluation of Tetraselmis sp. CTP4 Microalgal Biomass Produced in Industrial Photobioreactors

“…Indeed, novel sources for this pigment might be important, because the lutein market size (USD 135 million in 2015) is estimated to generate significant gains in the near future [43]. A strong application outlook in eye health supplements may favour product demand, since lutein from microalgae (E161g) has been approved both in the EU and USA as a colour additive.…”

Keggin‐type Heteropolyacids‐Catalyzed Selective Hydrothermal Oxidation of Microalgae for Low Nitrogen Biofuel Production

“…[18] On the one hand, the bio-oil yield increases with the increase of reaction temperature initially since higher reaction temperature is conducive to the decomposition of cellular organic compounds. [19,20] On the other hand, the bio-oil yield starts to decrease due to the increased gasification of algal biomass and polymerization of intermediates when the temperature is above 350°C. This confliction promotes the development of catalytic HTL technologies to improve the biocrude yield under mild conditions.…”

“…Given the thermochemical conversion degrees of microalgae is strongly temperature‐dependent, an appropriate reaction temperature of HTL is a dominant parameter affecting the yield and quality of bio‐oil [18] . On the one hand, the bio‐oil yield increases with the increase of reaction temperature initially since higher reaction temperature is conducive to the decomposition of cellular organic compounds [19,20] . On the other hand, the bio‐oil yield starts to decrease due to the increased gasification of algal biomass and polymerization of intermediates when the temperature is above 350 °C.…”

Pilot Production of Spirulina Biomass and Obtaining of Novel Biodegradable Surfactants

“…Their high photosynthesis indices, due to the simplified single-celled structure, allow them not only to serve as an efficient platform for carbon sequestration, but also to quickly accumulate lipids in their biomass (up to 77%). Even when using the conservative way of obtaining, microalgae still produce about 10 times more lipids per unit area of land than a typical ground oil-plant [12].…”