In the industrial synthesis of D-alpha-p-hydroxyphenylglycine the separation of amino acid is carried out by precipitation. During this process, a mother liquor is produced with a high salt content (2 M phosphates and sulphates) and an amino acid concentration of 0.11-0.12 M. The disposal of this mother liquor causes an environmental problem and an economic loss. The salt content of this mother liquor can be reduced in 70% of the initial by means of an electrodialysis process previously carried out by us, with only an amino acid loss of 15% of the initial. To improve and simplify this process, an electro-electrodialysis process (a membrane electrolysis process; the electrode processes and the transport process across the membrane are used) has been developed in which as a first step, the electro-neutralisation of solutions containing sulphuric acid and D-alpha-p-hydroxyphenylglycine is studied. The sulphuric acid content is reduced to 87% of the initial, without detected loss of amino acid, The final solution is posteriorly neutralised by working up the pH of the solution for precipitating the amino acid, and a mother liquor with approximately 0.10M D-alpha-p-hydroxyphenylglycine and a low salt content (0.08 M Na2SO4) is produced. This mother liquor with low salinity can be recirculated again to a new electro-electrodialysis process.