FIELD: biotechnology, biochemistry. SUBSTANCE: method involves enzymatic reaction of L-lactic acid with oxygen in an aqueous solution in the presence of enzymes - glycolate oxidase (oxidase of (S)-2- -hydroxyacids) and catalase. The latters can be soluble enzymes or microbial cell-transformants, in part, Pichiapastoris NRRL Y-21001 or Hansenula polymorpha NRRL Y-21065. Soluble enzymes are used at their activity 0.01-1000 IU/ml (glycolate oxidase) and 50-5000 IU/ml (catakase). Process is carried out at pH 7-9. Preferable enzyme activities for glycolate oxidase and catalase are 0.1-10 and 2000-15000 IU/ml, respectively, and at ratio of IU/ml of catalase to glycolate oxidase at least 250:1. Method provides high yield of the end product (96%) and high purity of product (98% for sodium salt). EFFECT: improved method of producing, increased yield and purity. 5 cl, 1 tbl, 17 ex
