Refining method of tryptophan

The invention discloses a refining method of tryptophan. The tryptophan refining method comprises the following steps: dissolving a tryptophan crude product in an acid solution or an alkali solution to obtain a mixed solution, the pH value of the acid solution being 0.5-2.5; decoloring the mixed solution, and filtering to obtain filtrate; under the heating condition, the pH value of the filtrate is adjusted to 4.6-5.8, and crystals are obtained; and separating and drying the crystal to obtain tryptophan. The method provided by the invention is simple in steps and convenient to operate, and high-purity tryptophan can be obtained. 本发明公开了一种色氨酸的精制方法。所述色氨酸的精制方法包括：将色氨酸粗品溶解到酸溶液或碱溶液中，得到混合溶液，其中，所述酸溶液的pH为0.5-2.5；对所述混合溶液进行脱色后，过滤，得到滤液；在加热条件下，调节所述滤液的pH值为4.6-5.8，得到晶体；将所述晶体分离干燥，得到色氨酸。采用本发明提供的方法，步骤简单，操作方便，且能够得到高纯度的色氨酸。