Characterization of wet microalgal cells pretreated with steam for lipid extraction

Steam pretreatment was employed to disrupt microalgal cells for lipids extraction. Effects of steam pretreatment on microstructure of microalgal cells were investigated through scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Effect of treatment on lipid extraction was also studied. Microalgal cell walls were distorted after steam pretreatment due to the hydrolysis of organic macromolecules contained in cell wall. Maximum curvature was increased from 1.88 x 10(-6) m(-1) to 1.43 x 10(-7) m(-1) after treatment with the steam at 130 degrees C. The fractal dimension of microalgal cells increased from 1.25 to 1.30 after pretreatment for 15 min, and further increased to 1.47 when the pretreatment time was increased to 60 min. Increased steam pretreatment temperature and time enhanced the hydrolysis of organic macromolecules, and finally destroyed microalgal cell walls at pretreatment temperature of 130 degrees C and pretreatment time of 60 min. Lipid extracted from wet microalgal was significantly increased (2.1-fold) after pretreatment. (C) 2020 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd. All rights reserved.

Automated summary

Steam pretreatment was used to disrupt microalgal cells for lipid extraction, resulting in distorted cell walls due to hydrolysis of organic macromolecules. Increasing pretreatment temperature and time enhanced the hydrolysis and eventually destroyed microalgal cell walls. Lipid extracted from wet microalgal significantly increased after pretreatment.