Anselme Payen (French: [pa.jɛ̃]; 6 January 1795 – 12 May 1878) was a French chemist known for discovering the enzyme diastase, and the carbohydrate cellulose.
Payen was born in Paris. He began studying science with his father when he was 13-year-old, and later studied Chemistry at the École Polytechnique under the chemists Louis Nicolas Vauquelin and Michel Eugène Chevreul.
At the age of 23, Payen became manager of a borax-refining factory, where he developed a process for synthesizing borax from soda and boric acid. Previously, all borax had been imported from the East Indies exclusively by the Dutch. Payen's new method of synthesizing borax allowed him to sell the mineral at one third the going price, and break the Dutch monopoly.
Payen also developed processes for refining sugar, along with a way to refine starch and alcohol from potatoes, and a method for determination of nitrogen. Payen invented a decolorimeter, which dealt with the analysis, decolorization, bleaching, and crystallization of sugar.