Racemize 2-hydroxybutyric acid is usually synthesized by organic methods and needs additional deracemization to obtain optically pure enantiomers for industrial application. Here we present a cascade biocatalysis system in Escherichia coli BL21 which employed L-threonine deaminase (TD), NAD-dependent L-lactate dehydrogenase (LDH) alcohol (ADH) producing (S)-2-hydroxybutyric ((S)-2-HBA) from bul...

Studies were carried out on the formation of biodegradative L-threonine deaminase (EC 4.2.1.16) in resting cells of Escherichia coli. The results obtained are as follows: (1) The enzyme level was increased by adding L-threonine together with yeast extract to the cell suspension. (2) In the course of the enzyme formation, the addition of chloramphenicol or glucose to the medium resulted in insta...

A novel type of threonine-producing strains, dihydrodipicolinate synthase (DPS)-defective mutants of Brevibacterium flavum, was isolated as alpha-amino-beta-hydroxyvaleric acid (AHV)-resistant producers. The third selection markers used were a strong lysine inhibition of threonine production and a lower production of lysine than that of threonine in those derived from strains with feedback-sens...