The effects of the sonication parameters, including the power and time, were investigated for the effective isolation of Scenedesmus sp. from environmental microalgae communities when using fluorescence-activated cell sorting (FACS). The selectivity, defined as the percentage of Scenedesmus sp. successfully isolated and grown in microplates, appeared as peaks in contour plots spanned by the sonication power and time. For fast screening of the optimal sonication conditions, correlations between the selectivity and the statistical parameters from the FACS analysis were investigated. A graphical comparison analysis of the contour plots showed a pattern similarity of over 82% between the coefficients of variation for the side scatter (SSC-CV) and the selectivity. This predictability of the optimal sonication conditions enabled a Scenedesmus sp. selectivity of ca. 2 times using only one-third of the sonication condition sets arbitrarily chosen around the peaks of the SSC-CV, thereby saving resources and time for subsequent processes. (C) 2012 Elsevier Ltd. All rights reserved.