Ecological Engineering Helps Maximize Function in Algal Oil Production.

Algal biofuels have the potential to curb the emissions of greenhouse gases from fossil fuels, but current growing methods fail to produce fuels that meet the multiple standards necessary for economical industrial use. For example, algae grown as monocultures for biofuel production have not simultaneously and economically achieved high yields of the high-quality lipid-rich biomass desired for the industrial-scale production of bio-oil. Decades of study in the field of ecology have demonstrated that simultaneous increases in multiple functions, such as the quantity and quality of biomass, can occur in natural ecosystems by increasing biological diversity.

Process improvements for the supercritical in situ transesterification of carbonized algal biomass.

This work focuses on the production of biodiesel from wet, lipid-rich algal biomass using a two-step process involving hydrothermal carbonization (HTC) and supercritical in situ transesterification (SC-IST). Algal hydrochars produced by HTC were reacted in supercritical ethanol to determine the effects of reaction temperature, time, ethanol loading, water content, and pressure on the yield of fatty acid ethyl esters (FAEE). Reaction temperatures above 275 °C resulted in substantial thermal decomposition of unsaturated FAEE, thereby reducing yields.

Triflate-catalyzed (trans)esterification of lipids within carbonized algal biomass.

This study demonstrates the utility of rare-earth metal triflate catalysts (i.e., Sc(OTf)(3) and In(OTf)(3)) in the (trans)esterification of oleic acid as well as the lipids contained within carbonized algal biomass using ethanol in the presence of water.