Method for separating and extracting L-arginine from fermentation liquor

The invention discloses a method for separating and extracting L-arginine from fermentation liquor, which comprises the following steps: firstly, carrying out microfiltration on L-arginine fermentation liquor by a metal microfiltration membrane; and then, decoloring the obtained product; finally, sequentially carrying out reduced pressure evaporation, crystallization and refining on the decolored product. The method of the invention is simple and easy to operate, convenient in device maintenance and less in investment, and the adopted metal membrane is long in service time, has heat-resistance, acid-resistance, alkali-resistance and is easy to clean; the whole extraction process is performed by using a physical separation method, therefore, less acid, alkali and steam are consumed in the extraction process, and the extraction cost is greatly reduced; meanwhile, the method is mild in condition, is simple in operation, is few in separation steps, is less in waste water discharge, is high in yield, is good in product quality, and the like; and through analysis, the purity of the L-arginine product obtained through alcohol-precipitation and crystallization reaches over 99 percent.