GB887879A - Process for producing glutamic acid from beet sugar waste - Google Patents

Abstract

Glutamic acid or salts thereof (e.g. alkali metal, alkaline earth metal and hydrochloride salts) are prepared from beet sugar waste by acidifying such waste with a strong acid such as sulphuric, hydrochloric, oxalic or phosphoric acid, allowing the slurry obtained to descend in a dispersed state in an extraction tower such as a perforated plate tower or a spray tower, causing a sparingly-soluble organic solvent (of which not more than 25 grams are soluble in 100 grams of water at 25 DEG C.) to ascend as a continuous phase in said tower, allowing the extract obtained to overflow from the upper part of the tower, holding the extracted waste solution near the bottom of the tower at a constant interface level for sufficient time to release at least part of the solvent contained therein, introducing the solvent into the continuous phase of solvent above said constant level of the extracted solution so that no emulsification takes place during the continuous liquid-slurry extraction, re-extracting pyrrolidone carboxylic acid contained in said extract with water which may contain an alkali, hydrolysing the thus obtained aqueous extract, extracting the hydrolysate with a sparingly soluble organic solvent (as previously defined) to remove impurities, adjusting the aqueous solution to a suitable pH and crystallising glutamic acid or salts thereof from said aqueous solution. Specified sparingly soluble organic solvents are butanol, amyl alcohol and fusel oil. The initial acidification of the beet sugar waste is preferably taken to a pH of less than 3 before the extraction. The extraction effect may be improved by giving pulsations to the continuous phase of the solvent.