Porous chemical pretreated Saccharomyces cerevisiae was used as support, stabilizer, and reducing agent for the rapid green synthesis of gold nanocatalyst. Au nanoparticles (Au NPs) were generated through in-situ reduction of the absorbed Au(III) by the reductive functional groups of mannoproteins in yeast cell wall. The obtained spherical mono-dispersed Au NPs have an average particle diameter of 9.99 +/- 1.63 nm as evidenced by TEM image, and exhibits excellent catalytic activity for the dechlorination of quinclorac to 8-quinoline-carboxylic acid by sodium borohydride. The reductive dechlorination of quinclorac is chemical reaction controlled and follows pseudo-first-order kinetic model. The rate constant increases with the increase of the temperature and decrease of the initial quinclorac concentration. The present synthesis protocol of Au nanocatalyst has the advantages of rapid, convenient and mild operation, high catalytic dechlorination efficiency and organic solvent-free nature. (C) 2017 Elsevier B.V. All rights reserved.