PRODUCTION OF L-ASPARTIC ACID

摘要

PROBLEM TO BE SOLVED: To efficiently obtain industrial crystal L-aspartic acid having a specific crystal size from an inexpensive raw material by a simple process, accompanying maleic acid (salt), by enzymatically reacting maleic acid with ammonia. SOLUTION: A substrate medium containing maleic acid and ammonia and/or ammonium maleate is treated with a bacterium (e.g. Alcaligenes faecalis ATCC8750) having maleic isomerase activity and aspartase activity to form L-aspartic acid. Maleic anhydride and/or maleic acid is added to the reaction mixture and L-aspartic acid crystal is precipitated with an acid and collected. Ammonia is added to the remaining mother liquor and is reused as a substrate medium to give the objective crystal L-aspartic acid accompanying 0.01-15wt.% of maleic acid and/or its salt and having 50-500μm crystal size industrially and advantageously.