METHOD FOR THE PREPARATION OF LACTIC ACID

A method for preparing a fermentation product comprising lactic acid， said method comprising: a) treating lignocellulosic material with caustic magnesium salt in the presence of water to provide treated aqueous lignocellulosic material; b) saccharifying the treated aqueous lignocellulosic material in the presence of a hydrolytic enzyme to provide a saccharified aqueous lignocellulosic material comprising fermentable carbohydrate and a solid lignocellulosic fraction; c) simultaneously with step b)， fermenting the saccharified aqueous lignocellulosic material in the presence of both a lactic acid forming microorganism and caustic magnesium salt to provide an aqueous fermentation broth comprising magnesium lactate and a solid lignocellulosic fraction; d) recovering magnesium lactate from said broth， wherein said saccharification and said fermentation are carried out simultaneously. In an embodiment， the method further comprises: e) providing， as an aqueous solution or a gas， a feed comprising hydrogen chloride (HC1); and， f) acidifying the recovered magnesium lactate to lactic acid by bringing said magnesium lactate into contact with said feed comprising HC1， thereby forming a liquid effluent comprising lactic acid and MgCla.