Combining experimental evaluation, process simulation, and life cycle assessment of green and bio-based solvents for the extraction of β-carotene and cellular lipids from Rhodosporidium toruloides

Substituting traditionally used harmful solvents to extract valuable bioactive components is crucial for reducing environmental harm, increasing user safety, and advancing process sustainability. This study evaluates four green and bio-based biphasic solvent systems 2-methyltetrahydrofuran (2-MeTHF)/(ethanol or 1-butanol)/water and cyclopentyl methyl ether (CPME)/(ethanol or 1-butanol)/water, against two conventional biphasic solvent systems, chloroform/methanol/water and hexane/ethanol/water, for β-carotene and cellular lipids extraction from the oleaginous yeast Rhodosporidium toruloides. Laboratory-scale extraction experiments determined yields, solvent consumption, and evaporation energy requirements for each system. Afterwards, the selected systems were simulated with Aspen Plus to obtain mass and energy balances for industrial-scale operation. These results formed the basis of a cradle-to-gate life cycle assessment (LCA) using the EF 3.1 method, applying functional units of 1 kg extract and 1 g β-carotene. Experimentally, 2-MeTHF-based systems achieved the highest total extraction yields (0.25 gextract/gDCW) and β-carotene yields (0.046 mg/gDCW), outperforming CPME and matching or exceeding conventional systems. Aspen Plus simulations indicated the lowest solvent consumption for 2-MeTHF/ethanol/water and the lowest thermal energy demand for chloroform/methanol/water. The LCA results showed that 2-MeTHF/ethanol/water exhibited the lowest climate change impact per kg extract, while 2-MeTHF/1-butanol/water performed best per g β-carotene. CPME-based systems had higher impacts, largely due to greater solvent and energy requirements, though results may be influenced by limited industrial-scale inventory data.