title: Fractal microstructure characterization of wet microalgal cells disrupted with ultrasonic cavitation for lipid extraction.
abstract: The effects of ultrasonic treatment on fractal microstructures of wet microalgal cells were investigated for lipid extraction. Fractal dimension of cells with distorted surfaces increased with power and ultrasonication time. Microalgal cells shrank owing to dehydration and cytomembranes were reduced to debris, but cell walls were not fragmented. When ultrasonication power increased from 0 to 500W for 30min, the fractal dimension of cells increased from 1.21 to 1.51, cell sizes decreased from 2.78 to 1.68μm and cell wall thickness decreased from 0.08 to 0.05μm. When ultrasonication time increased from 5 to 30min with a power of 150W, the fractal dimension of cells increased from 1.24 to 1.37, cell sizes decreased from 2.72 to 2.38μm and cell wall thickness first increased to a peak of 0.22μm and then decreased. Long-chain and unsaturated lipids were degraded into short-chain and saturated lipids with ultrasonic cavitation.
authors.affiliation: State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China. Electronic address: juncheng@zju.edu.cn.
authors.forename: Jun
authors.initials: J
authors.lastname: Cheng
authors.affiliation: State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China.
authors.forename: Junhu
authors.initials: J
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China.
authors.forename: Kefa
authors.initials: K
authors.lastname: Cen
mesh_terms: D002462:Cell Membrane / Q000473:pathology / Q000528:radiation effects*; D048429:Cell Size / Q000528:radiation effects; D002708:Chlorella / Q000528:radiation effects / Q000648:ultrastructure*; D004307:Dose-Response Relationship, Radiation; D017709:Fractals; D019220:High-Energy Shock Waves; D008055:Lipids / Q000302:isolation & purification*; D058086:Microalgae / Q000528:radiation effects / Q000648:ultrastructure*; D008854:Microscopy, Electron; D013997:Time Factors
chemical_list: D008055:Lipids
keywords: Cells; Fractal dimension; Lipids; Microalgae; Ultrasonication