A bio-based surfactant was prepared by chemical modification of kraft lignin. Herein, grafting of butyric anhydride (BA), 3-(trimethoxysilyl) propyl methacrylate (MPS) and 2-bromoisobutyryl bromide (BIBB) onto kraft lignin were conducted to change its amphiphilicity and the chemical reactions were confirmed by FTIR, H-1 NMR, GPC, TGA and P-31 NMR. The lignin modified with MPS and BIBB was only partially dissolved in organic monomers due to the low grafting ratio. In contrast, over 95% of the hydroxyl group conversion was achieved when BA was used. The BA modified lignin (lignin-B) was found to be completely soluble in the monomers. The interfacial tension measurement indicated the capability of lignin-B to decrease the interface energy between water and styrene from 35 J m(-2) to 15 J m(-2). As the result, a stable water-in-oil emulsion was achieved using lignin-B as the emulsifier. The average diameters of emulsion droplets were 499.4 nm and 363.9 nm with a lignin-B content of 0.5 wt% and 5 wt% respectively. Due to both steric and electrokinetic effects, the as-prepared water-in-oil emulsion was kept stable over 30 days. These results suggest that lignin-B has a promising potential to be used as a bio-based surfactant. (C) 2017 Elsevier Ltd. All rights reserved.