Reviewing Ethanol Liquefaction of pretreated natural microalgae in producing algal biofuel

Abstract

Algae has shown great promise as a possible leader in reducing CO₂ emissions through biodiesel production. It is able to fix nitrogen, phosphorus, and heavy metals. Algae has a short growth cycle, low requirements for growth condition, and the ability to cultivate on non-arable land. New methods are beginning to use all product of algae biomass to generate a higher quality of biofuel. Conversion discussed in the article includes a pretreatment of raw microalgae by Soxhelt extraction of lipids or hydrothermal treatment for extraction of saccharides and proteins, and liquefaction of raw and pretreated samples in sub/supercritical ethanol. The composition of biocrude from the raw algae was complex, the biocrude from lipid extracted algae had poor quality, and the extraction of saccharides and proteins by hydrothermal pretreatment simplified the composition, reduced the nitrogen content, and improved the higher heating value for biocrude. Still, algal biofuels are not ready to compete in the oil and gas industry, but proves that the algae research is heading in the right direction.