In this study, bioflocculant from Cobetia marina L03 could be used for effective harvesting of the microalgae Chlorella vulgaris via flocculation-flotation. A flotation efficiency of 92.7% was observed when 20 mg L-1 bioflocculant was tested for flocculating the microalgal cells with 5 mM CaCl2. The bioflocculant was stable at wide ranges of pH and temperature, which is advantageous for its application under various conditions. Chemical analysis of the bioflocculant indicated that it is composed of 31.6% total sugar and 0.2% protein (w/w). This bioflocculant has potential for the high-efficiency harvesting of microalgae and may be useful in reducing one of the barriers to microalgal biofuel production. (C) 2015 Elsevier Ltd. All rights reserved.