Thalassiosira pseudonana and Skeletonema costatum biomass optimization: Cultivation, harvesting, extraction of oils and biodiesel and pelletization of the residue

• Published in: Journal of sea research 2022-09, Vol.187, p.102243, Article 102243
• Main Authors: Iglesias, S., Míguez, C., Sánchez, A., Cancela, A., Álvarez, X.
• Format: Article
• Language: English
• Subjects: aluminum; biodiesel; biomass; Biorefinery; biorefining; chloroform; climate change; energy; fatty acid composition; feedstocks; flocculation; fuel production; Harvesting; ionic strength; iron; manufacturing; methanol; Microalgae; Oil extraction; palmitoleic acid; Pellet; pelleting; Skeletonema costatum; solvents; stearic acid; Thalassiosira pseudonana
• ISSN: 1385-1101; 1873-1414
• DOI: 10.1016/j.seares.2022.102243

Microalgae are one of the most promising feedstocks for biofuel production that can solve the energy crisis, climate change, and the depletion of fossil fuels. Biorefineries have production capacity bottlenecks that prevent them from being economically profitable, without leaving aside the environmental safety of by-products. This research aims to analyze critical stages such as harvesting or lipid extraction from two microalgae species currently unknown, such as Thalassiosira pseudonana and Skeletonema costatum. Inorganic flocculation with a low concentration of iron or aluminum salts (FeCl3 and Al2(SO4)3) was achieved to recover >60% biomass in just 20 min in both cases. Lipids extractions through chloroform: methanol (solvent ratio 2:1) obtained low performance due to the ionic strength medium. The fatty acid composition of the algae extracts showed that stearic acid (C18:0) and palmitoleic acid (C16:1) were predominant in both species. In addition, residues from the lipid extraction process were used for the manufacture of pellets. The data collected showed that these solid biofuels should be combined with other biomass typologies if the end-use are biomass boilers. The development of these studies provides new information on different microalgae species and their potential to use their biomass through an integrated utilization. [Display omitted] •Extraction of lipids from two currently unknown species of microalgae is discussed.•Inorganic flocculants recovered 60% of the biomass in only 20 min.•Oil extraction was carried out by combining chloroform/methanol in a 2:1 ratio.•Saturated fatty acids were the primary oil constituents for both microalgae.•Residues from the extraction process were used for the manufacture of pellets.