Valorization of Caribbean Sargassum biomass as a source of alginate and sugars for de novo biodiesel production

Abstract

Since 2011, a massive influx of pelagic brown algae Sargassum has invaded coastlines causing environmental and economic disaster. Valorizing this plentiful macroalgae can present much needed economic relief to the areas affected. Here the production of biodiesel and a high-value alginate stream using Sargassum biomass collected from the coast of Quintana Roo, Mexico is reported. Biomass was pretreated via AEA (Alginate Extraction Autohydrolysis) and enzymatic saccharification via fungal Solid State Fermentation, releasing 7 g/L total sugars. The sugar mixture was fermented using engineered Yarrowia lipolytica resulting in 0.35 g/L total lipid titer at the lab tube scale. Additionally, the capability of extracting 0.3875 g/g DW of a high-value, purified alginate stream from this material is demonstrated. The findings presented here are promising and suggest an opportunity for the optimization and scale up of a biodiesel production biorefinery for utilization of Sargassum seaweeds during seasons of high invasion.

Keywords: Biofuel; Biorefinery; Golden tide; Lipogenesis; Macroalgae; Yarrowia lipolytica.