title: Effect of sonication frequency on the disruption of algae.
abstract: In this study, the efficiency of ultrasonic disruption of Chaetoceros gracilis, Chaetoceros calcitrans, and Nannochloropsis sp. was investigated by applying ultrasonic waves of 0.02, 0.4, 1.0, 2.2, 3.3, and 4.3 MHz to algal suspensions. The results showed that reduction in the number of algae was frequency dependent and that the highest efficiency was achieved at 2.2, 3.3, and 4.3MHz for C. gracilis, C. calcitrans, and Nannochloropsis sp., respectively. A review of the literature suggested that cavitation, rather than direct effects of ultrasonication, are required for ultrasonic algae disruption, and that chemical effects are likely not the main mechanism for algal cell disruption. The mechanical resonance frequencies estimated by a shell model, taking into account elastic properties, demonstrated that suitable disruption frequencies for each alga were associated with the cell's mechanical properties. Taken together, we consider here that physical effects of ultrasonication were responsible for algae disruption.
authors.affiliation: Department of Pure and Applied Physics, Faculty of Engineering Science, Kansai University, Osaka 564-8680, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Kurokawa
authors.affiliation: The Sonochemistry Group, Faculty of Health and Life Sciences, Coventry University, Coventry CV1 5FB, United Kingdom.
authors.forename: Patrick M
authors.initials: PM
authors.lastname: King
authors.affiliation: National Centre of Applied Microfluidic Chemistry, Pohang University of Science and Technology, Gyeongbuk 37673, Republic of Korea.
authors.forename: Xiaoge
authors.initials: X
authors.lastname: Wu
authors.affiliation: Irish Water, Dublin 1, Ireland.
authors.forename: Eadaoin M
authors.initials: EM
authors.lastname: Joyce
authors.affiliation: The Sonochemistry Group, Faculty of Health and Life Sciences, Coventry University, Coventry CV1 5FB, United Kingdom.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Mason
authors.affiliation: Department of Pure and Applied Physics, Faculty of Engineering Science, Kansai University, Osaka 564-8680, Japan. Electronic address: ken@kansai-u.ac.jp.
authors.forename: Ken
authors.initials: K
authors.lastname: Yamamoto
mesh_terms: D017377:Diatoms / Q000737:chemistry*; D014465:Ultrasonics
keywords: Algae; Disruption; High-frequency ultrasonic; Physical effects