Fermentation and purification process for succinic acid

Abstract

A process for economically producing highly purified succinic acid comprises growing a succinate-producing microorganism on a low cost carbohydrate substrate; simultaneously neutralizing the fermentation broth and precipitating the succinate as calcium succinate by adding a calcium ion source to form calcium succinate; isolating the calcium succinate; slurrying the calcium succinate in water and treating it with sulfuric acid to form calcium sulfate and succinic acid; and then treating the succinic acid with first a strongly acidic ion exchanger and then a weakly basic ion exchanger to remove impurities and obtain a highly purified succinic acid product. In a preferred embodiment, the calcium succinate is isolated from the fermentation broth by filtration; the filtrate is heated to precipitate additional calcium succinate; and, the spent filtrate which contains nutrients is recycled to the fermentor.

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