Method for secondary extraction of mycoprotein in amino acid extraction mother liquor

The invention belongs to the technical field of amino acid protein extraction, and discloses a protein secondary extraction method of amino acid extraction mother liquor, and the protein secondary extraction method of the amino acid extraction mother liquor comprises the following steps: pretreating glutamic acid extraction mother liquor to obtain pretreated glutamic acid extraction mother liquor; extracting the pretreated glutamic acid extraction mother liquor by a protein air flotation-precipitation method to obtain crude mycoprotein precipitate and supernate; and carrying out filter pressing, centrifugation, drying and vacuum concentration treatment on the crude mycoprotein precipitate and the supernatant to obtain a product protein, a fertilizer stock solution and concentrated distilled water. According to the method, the protein extraction yield of the glutamic acid extraction mother liquor is increased by 2.7%-3.2%, the protein residue of the filtrate after protein extraction is reduced to 2% or below f