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High-efficiency cell disruption and astaxanthin recovery from Haematococcus pluvialis cyst cells using room-temperature imidazolium-based ionic liquid/water mixtures

Choi, Sun-A, Oh, You-Kwan, Lee, Jiye, Sim, Sang Jun, Hong, Min Eui, Park, Ji-Yeon, Kim, Min-Sik, Kim, Seung Wook, Lee, Jin-Suk
Bioresource technology 2019 v.274 pp. 120-126
Haematococcus pluvialis, ambient temperature, anions, antioxidants, astaxanthin, energy conservation, hexane, ionic liquids, lipids, sulfates
Energy-saving, high-efficiency cell disruption is a critical step for recovery of thermolabile antioxidant astaxanthin from Haematococcus pluvialis cyst cells of rigid cell-wall structure. In this study, as room-temperature green solvents, 10 types of 1-ethyl-3-methylimidazolium ([Emim])-based ionic liquids (ILs) were compared and evaluated for their abilities to disrupt H. pluvialis cyst cells for astaxanthin/lipid extraction. Among the 10 ILs tested, 3 [Emim]-based ILs with HSO4, CH3SO3, and (CF3SO2)2N anions were selected based on astaxanthin/lipid extraction performance and synthesis cost. When pretreated with IL/water mixtures, intact cyst cells were significantly torn, broken or shown to release cytoplasmic components, thereby facilitating subsequent separation of astaxanthin/lipid by hexane. However, excess IL pretreatments at high temperature/IL dosages and longer incubation times significantly deteriorated lipid and/or astaxanthin. Under optimized mild conditions (6.7% (v/v) IL in water solution, 30 °C, 60 min), almost complete astaxanthin recoveries (>99%) along with moderate lipid extractions (∼82%) could be obtained.