A study to investigate the energy recovery potential from different macromolecules of a low-lipid marine Tetraselmis sp. biomass through HTL process

Abstract

This study investigated the hydrothermal liquefaction (HTL) of extracted major macromolecules from Tetraselmis sp. biomass. The carbohydrate fraction was first recovered from Tetraselmis biomass using pressurized heated water. The crude lipid fraction was then extracted from carbohydrate-free biomass by hexane. The remaining biomass was considered as protein extract. HTL runs were conducted from 275 to 350 °C and 30 min for each extract; the maximum biocrude yields for carbohydrate, lipid, and proteins were obtained at 325, 325, and 350 °C, respectively. Next, HTL runs of these macromolecules were conducted at 350 °C for 10–60 min. The highest biocrude yields from carbohydrate, lipid, and protein extracts were obtained at 45, 20, and 45 min, respectively. The optimal energy recovery, as biocrude, from carbohydrate, lipid, and protein extracts were 41, 85, and 81%, respectively. Therefore, microalgae biomass with low carbohydrate content or carbohydrate-extracted biomass could be used as feedstock for biocrude production.