Lipid Extraction from Various Species of Wet Microalgae Using Liquefied Ammonia

TL;DR

This study shows that using liquefied ammonia to extract lipids from wet microalgae is efficient and preserves cell structure, making biofuel production more cost-effective.

Contribution

The study demonstrates the versatility of liquefied ammonia for lipid extraction across multiple microalgal species without energy-intensive steps.

Findings

Liquefied ammonia extracted 25.6–70.6 wt% of the sample's dry weight as crude lipid extract.

Fatty acid methyl ester yields were 5.5–17.4 wt%, comparable to or better than traditional methods.

The method preserved microalgal cell structure, increasing the value of residual solids.

Abstract

Energy-intensive
drying or cell-disruption processes in lipid extraction
procedures reduce efficiency and increase the cost involved in producing
biofuels from microalgae. Recently, a simple method was proposed for
extracting lipids directly from microalgae by utilizing liquefied
ammonia (NH3(l)), which eliminates the energy-intensive
processes. In the present study, the versatility of NH3(l) extraction was assessed by applying it to six microalgal species
with different contents of lipids. This method directly separated
25.6–70.6 wt % of the dry weight of the sample as crude extract.
The total fatty acid methyl ester yield was 5.5–17.4 wt %,
comparable to or exceeding that obtained by traditional approaches.
The crude extract was highly enriched with valuable C12–C24
fatty acids. Furthermore, scanning electron microscopy showed that
after NH3(l) extraction, the cellular structure of the
residue was preserved. These results suggest that employing the NH3(l) extraction method enhances applicability and consequently
increases the process value by separating components into extract
and useful residual solids.

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